What do I do if I cannot fix an error that is universal in all Unity games? Is there a way to reset everything related to Unity?

For as long as I can remember, I have had a large error in Unity games that has impacted my ability to play Unity games greatly. Whatever I do, in every Unity game, the down key is permanently held down, even when I’m not pressing it. The only possible fix is overriding it by holding the up key, but that’s to much of a hassle for me when I want to play games. This happens in games that use arrow keys and WASD, and I haven’t been able to find a fix. The only thing I’ve been told is to try a new keyboard, but that does not work.
Considering my little knowledge in coding and game creation, the advice I see online is very hard to follow, and I don’t know what I am doing when I try it. So, is there a way to fully reset everything related to Unity on my PC, like a “factory reset?” That may be what I’ll have to do to fix this issue. Thanks for any advice.

Do you keep any other devices plugged in? Like a joystick or Xbox controller?