Primary care physicians are often switchboard operators - they hook you up with potential resources or referrals that may lead to a solution. The chances that any given PCP is going to know a lot about RSI is pretty small, they have literally the entire spectrum of human health to consider, not to mention the looming issues of obesity, heart disease, cancer, and other more damaging syndromes.
Personally, I found wrist pain to be of multifactorial origin: too much typing, driving, playing piano, not enough cardio, strength training, and relaxation vs. stress.
This is true, and I certainly don't blame PCPs for not being up to date on the specifics of low-frequency disorders like RSI.
But my frustration is that even the 'switchboard' component of PCPs seems to be broken on this topic - across several musculoskeletal issues, I've only ever gotten recommendations to surgeons (who then said "you're not sick enough yet"). PCPs didn't even know what kind of specialist to suggest for finding causes and reducing pain, and the internet wasn't much better.
At risk of saying "what worked for me", talking to a physical therapist was a huge help with each problem - they didn't have cures, but their education was much more relevant to saying "here are some common risk factors and pain reducers you could look into".
And yes - 'multifactorial' seems like the usual answer, so I'm not surprised everyone has a different fix.
I have the same experience. Doctors and physiotherapists were of no help to me - they had no experience with RSI. In the end I found my own solution that worked:
https://github.com/melling/ErgonomicNotes
One example is John Ousterhout, the creator of Tcl/Tk, has had RSI for decades:
https://web.stanford.edu/~ouster/cgi-bin/wrist.php