Unfortunately I was probably what most people would think is a model person in terms of activity. I used a standing desk or sitting with no backrest to maintain upright posture - I exercised all the time, did yoga with my wife, competed in powerlifting, did plenty of walking/cardio, rucking etc. I played guitar regularly and had since I was like 12 and had bouldering as a hobby so finger strength didn't seem to be an issue.

I did physical therapy for months and the issue basically came down to my nerves being the issue. I was diagnosed with Cubital Tunnel Syndrome in both elbows and also a torn TFCC tear in one hand causing pressure on the ulnar nerve in my wrists when the wrist was flexed even a little or in what was called ulnar deviation (wrist extended outwards/away from your body). I was told the most likely cause was as simple as the way I slept - with my elbows bent and potentially exacerbated due to excessive heavy gripping combined with my bone structure in my elbow simply not being very kind on me.

I've since recovered from the elbow surgeries and they are evaluating wrist surgery as well, I still sometimes have issues with my fingers going numb in the wrong position - but trust me, I went to all kinds of doctors trying to figure this out since practically every hobby I had required using my hands/fingers. Unfortunately it just seems like I was unlucky. But having keyboards that allow my hands to be in more natural positions at the very least has allowed me to continue working.