I switched from emacs to vim for the same reason. I was doing a lot of typing, and my left hand started aching when I was stretching my fingers and eventually it just started aching all the time. So I thought, why not try vim, which I had used many decades before.

Things were very slow for a few days, and there was a lot of swearing, as I got weird results from hitting a wrong key. But after about a week I was able to get along adequately, and after another one, I was at the point where I was making choices for optimal methods without really thinking about whether typing 2w would be better than holding j for a while.

I think the key was that I made the switch during a vacation, when my workload was lower and I would not be so frustrated by learning enough that I could select between methods.

Learning either vim or emacs in a rush is not good because you are likely to become habitualized on a small subset of methods, and will be blocked from learning other methods that will increase your productivity some day.