It's not just apple - windows and android autocorrect are more auto incorrect these days.

Your statement isn't incorrect - but I think it needs a slight qualification of "And none of them are acceptable". Both Apple and Android have regressed in quality and it's only possible because of a duopoly.

Is there a windows autocorrect? I thought that was a feature implemented by the individual program, not any sort of OS functionality.

I can't tell about windows - never used autocorrect there - but GBoard became laughable. I don't think I was able to use its suggestions since a few years. For instance, it will NEVER but really never put a uppercase I when I'm talking about myself. Never. I could select it from suggestions if I feel like, but I kinda gave up (this is written in Windows, that's why you see capital Is). Or my name, used quite often right, is also never spelled correctly - although it's there in the suggestions. I am using a yahoo email, GBoard knows the username, but it will ALWAYS suggest a gmail extension, which simply doesn't exist. I don't know any other keyboard which can properly handle multiple languages, so I'm stuck with GBoard, but it's nothing to be proud of.