What I've found to be most important is to relax. Press the keys smoothly and deliberately, without tensing your fingers and trying to maintain a stiff posture. Use a softer keyboard if you can. Your comfort and speed will go up.
This. I dislike mechanical keyboards largely for this reason. Apple's "modern" laptop keyboards (pre-butterfly) are the best I've ever used. For me, they have the right amount of pressure required and key travel to be able to type very fast (>100wpm) at very low effort.
Using this worries me so much that I'm just planting a ticking time bomb of RSI. I a slight ache every time I use it because you have to hit the keys so hard to ensure they register and the stop is so abrupt as paper thin plastic smacks against the metal.
Previous gen feels so gentle compared to it, and this is coming from someone who likes tactile mech keyboards.
I've heard others similarly complaining that the key travel being too low is like the feeling of running barefoot on a hard surface, and I agree --- on a good keyboard the actuation travel has to be very low to not tire the fingers, and a small tactile bump there is not bad, but the total travel should be relatively long and "bouncy" at the end to cushion the momentum of the fingers.
All rubber-dome keyboards are not alike either; some are stiffer than others, and some have higher actuation travel --- contrary to common advice, you don't have to "bottom out" a rubber dome switch if the inner membrane-actuating protrusion is long and "squishy" enough. Once it touches the membrane the switch actuates, but there's still a cushioning end-stop effect as the protrusion continues to deform.
Typing speed is an overrated fad (and in the worst cases an e-penis length contest) as in most cases when writing stuff (be it fiction, reports, code) your throughput isn't limited by typing speed.
Avoiding injuries on the other hand is invaluable.
Even now, just getting into the thread makes my wrists tingle
This very much depends per switch. For example, Cherry MX Red require far less pressure than Cherry MX Blue. There's also the issue of noise (which is annoying for other people, and allows for a TEMPEST attack).
Optical switches, such as the Wooting (2) require also less travel.
I made the admittedly-difficult switch to Dvorak and that went away almost immediately. My typing speed is on-par with what it was with QWERTY. I can type out conversational English in real time, and that's about my functional limit. I don't consider that a selling point, but for those of you with wrist pain I can wholeheartedly recommond Dvorak.