Based on my own experience, I don't think any of this is necessary.
Context: Back about twenty years ago; startup; spending 18 hours a day, 7 days a week for about 2 years almost full time in front of the computer coding, electronics design, 3D CAD, etc.
I developed pain and soreness on both wrists. Inflammation too. They were warm to the touch. I resorted to things like coding with ice packs on my wrists. It sucked.
I also had context from work in another industry where I knew people who had surgery on their wrists due to the pain and inflammation. Not fun at all. And, no, it did not solve the problem.
Other than repetitive motion, the root cause is bad ergonomics. Splitting the keyboard or using two keyboards does not solve the problem.
You need four things:
1- A low actuation effort keyboard
2- A trackball --mice are horrible, they require far more motion and effort than the task demands
3- A good adjustable chair (Aeron is what I use) with adjustable arm rests
4- An ergonomic desk, not an office desk
#4 is where I went to work and designed my own [0] [1]. The other factors are somewhat subjective and require you to experiment until you find what you like.
The effect was almost instantaneous. You setup your chair to match the arm rest height to that of the wrist support bar on the desk. And you relax. You have to learn to relax. You hand naturally droops into the cavity where the keyboard and trackball are. The objective is minimal to no attitude (orientation) support tension on the upper tendons. When you eliminate this tension, the problem is gone.
The trackball makes it so you don't have to move all over the place to use the GUI. This is particularly true of a multimonitor or large monitor setup. Sorry to say this --because I know there are people who like them-- mice are horrible. The same is true of touch pads. Great for low cost integration into thin laptops, horrible for ergonomics. I use a trackball on my laptops as well.
If this worked for me (18 hours/day, 7 days a week, 2 years) it has to work for anyone doing less than that.
Normal office desks are horrible. They are a relic of the days when people wrote on paper by hand. A modern ergonomic desk designed for extended work on computers cannot have a single flat surface at 29 inches (74 cm) of height. That's ridiculous. The ergonomics of using a keyboard and mouse/trackball on such a surface are 100% wrong.
Measure the height from your elbow to the floor while relaxed on your chair. Femur bone should be horizontal, feet comfortably touching the ground, spine is comfortably vertical (not slouching), shoulders relaxed, forearm bent at 90 degrees (horizontal). Is that 29 inches? Nope. It's probably in the 25 to 26 inch range (63.5 to 66 cm). Guess the height of the keyboard shelf on my custom desk? The wrist support bar is about 1.5 inches (4 cm) high, sanded to about 600 grit and stained with Tung oil. It's reasonably friction free, not sticky or perspiration-inducing. The edges are rounded to, if I remember correctly, a 1/2 inch (1.3 cm) radius).
[0] https://i.imgur.com/S8gOPh7.jpg
[1] https://i.imgur.com/PoKDNOk.jpg