I'm 27 and my wrists/fingers are constantly hurting from 15 years of non-stop PC gaming. Before tinnitus it used to be my number 1 problem and I've tried a ton of things aswell. I like to think it's working so far - here's my few tips
1. have a job during the day. I know this sounds unhelpful and easy but it really is the foundation of recovering. All these hours spent away from a PC is where it heals fastest. If you have to use a mouse at your job, learn and use your least used hand for it (assumingly left hand for most). Opposite-sided mouse handling feels weird at first but you're gonna get used to it eventually. Bonus points for one of those pads with a cushion.
2. check your computer chair handle height. Adjust it a little higher (or lower?) to relieve pressure on the wrist
3. most important - change your mouse. I was too stupid and stubborn to switch away from a 5$ piece of garbage USB mouse that took superhuman strength to click. Suffice to say I paid the price with permanent weakness and hurt, but recently bought myself a much easier-to-click mouse (razor deathadder). It's amazing the good it does.
4. put your hands under warm water every hour or so and massage - more info
here
I don't even have a job currently and there's this fucking new sound disease, gaming is hard and I'm on antidepressants, my 16 year old pet that was my only breath of life in my tiny lonely appartment passed away, yet I'm starting to see the end of it all (in the good way). hang in there bud