I got a Redragon Devarajas as an entry hotswap mech keyboard, with the red switches to try to keep things quiet. It's based on an eVision PCB, and the red switches I got it with (Which are Redragon branded) are a close match to Outemu Red. But they don't really make it that quiet despite being linear, because there's no damping in the switch. There is a foam mat under the PCB, but it doesn't do much at all. Long story short, I put in Outemu Silent Peach V1 switches and now it actually is quiet, and easier on the fingers.
Long story long: All modern mechanical keyboards with "hotswap" key switches (which can be replaced without soldering, including while the keyboard is connected and in use) use switches shaped like Cherry MX switches, but they have an important variation: Whether the key switches have basically round (or square) pins, or flat pins. There is also another variation as well which is shared with the actual Cherry switches, which is whether they have 2 or 4 pins on them. These are confusingly called 3-pin or 5-pin switches, because there's either one or three plastic "pins" (which are nothing like the electrical pins) in the center of the back of the switch. These pins seem like alignment pins, but unfortunately they're shorter than the contact pins and not the other way around, so they're really only there to stabilize the switch when it's installed. The one-pin switches really don't have a problem with stability because they attach to the keyboard itself, which is why you need a puller to remove them.
The part on top where the key attaches to a keyswitch typically has either a plus-shaped stem called T-type, or that but sort of with brackets around it called box style. Some keys attach around the outside of the box, but most have a round part that goes onto the plus. Most keyswitches are now designed to be used with "backlit" keyboards with LED illumination, which can be a single color, a fixed layout with an assortment of colors, or "RGB" with adjustable colors - usually per-key. Most backlit keyboards which allow settings per-key (which requires either fancier LEDs or more controller pins) have a variety of animations and effects. The keyswitch housing has at least an open path for light from the circuit board to reach the key, and sometimes has a light pipe (just a piece of plastic really) for light to shine through in a more focused way.
Most keyboards have special layouts which permit them to use cheap keyboard controller chips with few inputs. On those keyboards, not only is there a maximum number of keys which can be pressed at once and still detected, but some keys simply cannot be detected when pressed at the same time. This is important for gaming, and pretty much nothing else. Being able to press multiple keys at once is called "rollover" because of the process of rolling the finger from one key to the next during certain actions in some types of games, and those keyboards where you can press any combination of keys (including all of them) and have them be detected correctly are said to have "n-key rollover", which is also confusing as this descends from the "n" essentially being a variable to begin with. The mechanical keyboards which don't have this feature use the "5-pin" switches, for reasons which have to do with the way their circuitry is designed.
The industry is now moving towards magnetic keyswitches, where the switch body can contain only a plunger with a magnet on it, and a return spring. The magnet's distance from the circuit board is read by a chip called a "hall effect" sensor. This is commonly used to give adjustable actuation and return height, the latter of which is the height to which the switch must be lifted before it can be pressed again. It can also be used to do neat tricks like joystick emulation, which can be used to give variable movement speed in games. The circuit boards are still quite a bit more expensive than the ones for traditional mechanical switch keyboards with non-spring moving parts and electrical contacts in the switches, and mechanical switches are very reasonable now, so both will still exist for the foreseeable future. Perhaps someone will come up with a practical means of printing the sensors on the circuit boards, which might actually make them cheaper than mechanicals.
Mechanical switches (while they're still here) are generally divided into three groups: Linear, tactile, and clicky. Linear switches do as little as possible to impede travel aside from spring force, and in fact are often lubricated, both by the factory and by modders. Tactile switches have designed-in unique feels related to their actuation points. Clicky switches are designed to make noise when actuated, and are usually also tactile. All of these switches can be designed with different actuation points and spring forces, and the force exerted on tactile switches varies throughout their travel. "Silent" keyswitches have internal buffers which cushion the plunger in the switch (to which the key is actually attached) so that the impact of the key is quieter, both when pressed and released.
Unbelievably, that is only a small portion of what could be said about keyboards, but it's everything needed to understand the longer version of the story, plus a little bit I threw in about magnetic keyboards that doesn't matter here but I found cool. Here goes:
The Redragon Devarajas is a 104-key, RGB, programmable keyboard in an aluminum case with hotswap mechanical keyswitches. You have a few different choices of switch. The Redragon red switches are approximately equivalent to Outemu red switches, both of them being 3-pin linear mechanical switches with about a 2mm actuation point, 4mm of total travel, and flat electrical contact pins. The Redragon switches have a black lower part, clear upper half, and a red box-style stem; Outemu's have a white base and a t-type stem. But Outemu also has a massive array of different keyswitches, which are mostly named after colors, and typically have housings which match them somehow. They started out with switches with simple color names and just colored stems, which was how the original Cherry MX switches were; they now have names like the Milk Tea (tan base, clear top, tan box stem) or Pink Jade (clear base, clear top, pink box stem.)
If you want to try out a bunch of switches, you can buy a switch "tester" kit which comes with some number of switches, and maybe a frame which holds the switches in a grid layout so you can test-push them, and some keys. Part of the appeal of these keyboards is that you can change the switches without soldering (which I've also done, because my first mechanical keyboard isn't hotswap capable) and I decided that I wasn't really happy with the red switches as I was beating up the pads of my fingers. What I wound up ordering was the outemu only 38 pc switches from INEDA and the Gateron 9 Key tester from Skyuo Store, both off of aliexpress. Total cost was $7.17 plus $6.97 (respectively) for 47 total switches and a frame with clear keys. I chose Outemu because the Redragon switches were reputed to be Outemu copies (I don't know that I've seen any evidence of this, in fact there are parts which are different which don't have to be, but they are very similar) and the Gateron because they also have the flat pins. I found out very quickly that I did not care for the Gateron switches, they all had a cheap, sloppy feel and yet also a lot of friction. They are considered to be reputable, but I didn't like them.
The 38 pcs Outemu assortment is a really nice sampling of their products, some of which I didn't care for either, but some are quite excellent. While I liked some of the tactile switches quite a bit, my favorites were the silent switches. Most of these are also lubricated, which allows them to have tighter tolerances and also smoother action. You can buy special tools for opening keyswitches so that you can lubricate them yourself, but prelubed switches really don't cost significantly more. After studying the specs, actually hammering on them, and looking at what was actually available for sale, I came down to two choices: The Silent Peach V1 (pink, light Pink, yellow box stem pre-lubed 3-pin silent linear switch with 40g actuation force, 2mm actuation point and 3.3mm of total travel) or the Silent Tom (grey, clear, grey box stem silent linear switch with 50g actuation force, 2.2mm actuation point and 3.3mm travel.) I settled on Peach because its 40g actuation is below rather than above the Red's 45g actuation, and it also has more difference between the actuation point and the end of travel than the Tom. I ended up getting those from INEDA as well, and 110 switches set me back only $20.54 with tax.
The keyboard came with cheap but functional switch replacement tools. The process using the factory tools goes like this: First, pull the caps with the tool which has the wires, which hook on the bottom of the key, and pull it up. Line them up so it's easy to put them in order later, unless they are dirty in which case you want to wash them in a bowl with a mild dish soap and warm water, without rough tools. This is especially true for dye sublimation printed clear key caps. If I wash them, I like to smack the water out of the key caps onto a towel before I air dry them. If the keyboard is dirty, hold it upside down (outside, probably) and clean it with a dry brush. I got a 2" wide paintbrush with a plastic handle at the dollar store for cleaning stuff like this; you can also get dedicated computer cleaning brushes with stiff bristles which are great. Holding it upside down while brushing it stops stuff from falling into the keyswitches; this is not a problem if they are dustproof types with a gasket and a light pipe, but for any other keyswitch it's an issue.
Now remove the switches by hooking the ends of the other tool onto the keyswitch at the top and bottom, where there are little tabs that hold them into the keyboard's upper frame, and squeeze it so that it presses in the tabs. Pull up evenly while squeezing, and the keyswitch should come out fairly easily. Pull all of the switches. Now turn the keyboard upside down again and whack it respectfully but effectively in a variety of directions to make anything loose fall out of it. If you had to do much cleaning in the first phase, you will probably have to do some here as well, and maybe more brushing.
Finally, reassemble the keyboard. Putting the switches back in is a slightly delicate process, and the most important part is that the pins line up with the holes they go into. Ideally you will be able to just put the switch in the hole and press down on the top and bottom of the upper case evenly, but you might have to give the process more thought than that. For my keyboard I found that I needed to press a little more firmly on the bottom (that is, on the part of the keyswitch closest to me, with the keyboard oriented like it would be if it was in use) for the pins to go in correctly. Embarrassingly, I also found I had bent one of the two pins on several of the switches during testing. I was able to straighten all of them using some small and high quality diagonal pliers, used delicately.
On Windows, or possibly Mac OS, you will want to download a keyboard tester so that you can conveniently be sure that every key is working. On Linux (or probably on Mac OS with X11 installed, it certainly used to have it) you can use xev for keyboard testing; run it in a terminal and select the window which pops up if necessary, put the mouse pointer inside of it, and all of the key up and down events will appear in the terminal. You can connect the keyboard to the system before putting in the switches, and then you will know immediately when the pins are going into their sockets because you will get at least one key down event, if not a flurry of key ups and key downs. Once you've got all the key switches working, you can pop the keys back on.
There's a jillion videos out there on all of this and more, so if you need more detail it's certainly out there. There's many different brands and kinds of switches and keys, and many different tools which can be used to make this process easier. But most keyboards will come with good enough tools to do the job. Just do yourself a favor and order a set with a decent number of extra switches.