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.

I have the same email @yahoo.com and @gmail.com (one is mostly for online shops etc), and the amount of time GBoard thinks it needs to recommend @gmail.com, it's obnoxious...

But the correction offers are still okay for me, I can mash keys around my email username and one of the corrections offered will be my username...

SwiftKey can handle languages, but it kind of sucks too , lol. It crashes all the time

No it cannot. SwiftKey has exactly two "languages": one is French, the other is German/English/Italian/Romanian. Yes it's a mash of all four, which makes the default swiped word and the suggestions exactly useless. Who the hell thought that was a good idea... only Samsung keyboard offers separate languages as well, but it's kinda worse in suggestions than GBoard.

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.