I'm in my 40s and I've noticed a similar thing. I've touch typed since I was a teen. My advice is to make note of which words you mistype, then plug them into a flash card system where you can type the answer out (Anki can be used in this way). Practice re-typing the mistyped words and things will (hopefully) improve. Another thing you can do is typing exercises. I find keyzen great for this: https://wwwtyro.github.io/keyzen/

Doing that once in a while made typing easier, and it also improved my pinky usage (I tended to avoid using them). Aside from that, I think it's just part of getting older. It's not you, it's just part of life.

If you use Windows, you can quickly erase a word when typing with Ctrl+Backspace. That can save a lot of time when correcting errors.

Best of luck! :-)