Working all day every glued to OEM mac accessories gave me RMD some years ago. Not sure if ever really healed.. so I'm just more mindful now.
I tried the Anker upright mouse which worked well for a while, but the claw-like pinching action bothered me after a while. This Logitech trackball has been great for the last year or two. Took a while to get used to, but now that I am, no different than a mouse. And having the additional left hand trackpad really helps when I need that interface.
You do have to clean it here and there, no different than an old school ball mouse. But a micro screw driver set makes it easy. Maybe once every 6 months?
Some peripherals I didn't include above.
Monitor is a Dell U2711 I've been using for a couple years. Might supplement with this 13" field monitor, as it's the closest thing to my laptop screen that I currently use as my 2nd monitor.
My mouse is the Anker ergonomic mouse, which you can pry from my cold dead carpel tunnel-free hand. I also use a Contour ShuttlePro. I may get a Logitech T650 if I find I miss my laptop's trackpad.
Haven't settled on a keyboard yet. Looking at the Logitech Craft.
I use this mouse. It costs $20:
http://www.amazon.com/Anker-Wireless-Vertical-Ergonomic-Optical/dp/B00BIFNTMC
At home I use an uplift adjustable desk I found cheap on Craigslist at the end of lockdown (the person was shifting back to in-person office work). They're pricey new, but make excellent desks. The surface is exactly 30" front to back. I've used these monitor arms at the office and they're pretty good. Generally you don't want your arms resting on the desk to begin with. Your wrists should be even with your forearms and elevated above the keyboard (using a rest and negative angle), possible resting on the arms of your chair if sitting or just hanging at your side if standing.
Biggest two tips for ergonomics I have are: switch to an ergo keyboard, and try out an ergo mouse. The mice aren't for everyone, but I've been using a cheap Anker for years now and it's absolutely fantastic. Similarly I've been using a Microsoft sculpt for about a decade, and have found it to be the best all-around solution for coding/writing. You could go even deeper with something like a Kinesis.
Understanding you want to try some out, but a coworker absolutely loves this: https://www.amazon.com/Anker-Wireless-Vertical-Ergonomic-Optical/dp/B00BIFNTMC
I'm a trackball fanboy and use a Logitech MX Ergo for limited wrist motion: https://www.amazon.com/Logitech-Ergo-Wireless-Trackball-Mouse/dp/B0753P1GTS