like many have said begin examination.
first how is the work area, are we talking about a cruddy setup where your in a wooden kitchen chair type deal?
are you straining your arms all the way out to type?
One thing to note is that over the years, one type of ergonomics just does not fit with another, because we all have different body types and levels of adjustment, as such we can only follow very broad advice to give.
i would start at the work area, are you comfortable, does back pain come into play, as stupid as it sounds back pain can lead to wrist pain, mainly cuz if your "core" is wrong then that could eminate further to your wrists and stuff.
we'll just assume that you have or will have a nice "body" torso and the screen is perfectly viewable so your not squinting or going "wtf is that" and you gotta nudge your neck in and crane to see something.
So lets talk about shoulders, are your shoulds sloutched or are your arms extended in such a wierd way that you could do a michael phelps front stroke?
or is your keyboard height and your shoulder elbow height so messed up your arms look end up looking like a T-rex arms in their resting position?
then look at your wrist placement does it hurt to when your giving a thumbs up and then twisting it to give a thumbs down? (think roman gladiator caesar)
then look at how your wrists are bent, are they relaxed or in a postion like how you push a grocery?
now we can examine if mech keyboards help, in most tests membrane keyboards take 70g of force to push down while what many will consider the ergnomic switch (cherry brown) takes 45g of force to push down.
personally i don't think it will alleviate everyones pain, i find it more enjoyable and isn't another checkmark one should take towards lessened rsi/cts.