I endorse most of Max's recommendations.
Based on my own experience I would definitely recommend being very cautious about RSI, i.e. especially resting carefully, as well as investing in solutions like more ergonomic devices, voice control, reading different resources (e.g. about good posture and different solutions) and visiting physiotherapists and other specicialists. I was largely unable to type or use a computer for 2-3 years due to RSI and I attribute a lot of this not having rested enough early on (despite the fact that I actually did reduce my activity quite dramatically almost immediately upon experiencing symptoms).
Another thing I would note is that although I think it's good to seek help from different experts, I would treat this very critically. I received completely conflicting, but entirely confidently expressed, diagnoses and recommendations from a number of different GPs, physiotherapists and consultant rheumatologists. Some of the literature I read myself also explicitly suggested that tendinopathies tended to be poorly understood by frontline medics, though I'm not in a position to evaluate whether that is the case (or at least true relative to other conditions). Some of the things which were recommended seem to have some evidence suggesting potential for harm (e.g. strengthening exercises, anti-inflammatories and immobilising wrist braces), so there are some grounds for caution.
One of the few things I would recommend that wasn't mentioned in Max's post, so far as I recall, and isn't mentioned in a lot of resources was keeping your hands warm, but I see you mentioned that in your own comment. There also seems to be some evidence that nutrition can be relevant for tendon healing (assuming that your RSI is related to your tendons): see this review. The main things they point to are vitamin C, taurine, vitamin A, glycine, vitamin E
A and leucine.
I'm also happy to talk about this 1-1 if you like.