I find that even when I set my country to UK and my language settings say 'British English', I'm still getting various autocorrections to US English to the point where I'm maintaining a list of dictionary overrides for words that us Brits spell differently (or have a distinction for), and there are plenty of words that it claims don't exist when a cursory dictionary search elsewhere proves otherwise.

It's mostly manageable on a laptop because it's easy to go back and edit text and make your computer behave. On a phone it's ducking^Wducking^Wfucking infuriating because you can automatically get the same correction a good two or three times before you can get the word you want, and you are very actively fighting a tool that is trying too hard to help, to the point it will deliberately misinterpret your keypress if it thinks it has a better idea of what you wanted to type.

Recently my Google keyboard's auto-correct has developed an annoying tendency to insert apostrophes when they're not needed (e.g. "its" -> "it's", "were" -> "we're"). Even manually deleting the suggestion only works until the next time I do need to write the contraction, whereupon it resumes "correcting" the non-contracted word every single time.

Only fix I've found is to manually make the word a shortcut for itself (e.g. shortcut "its" for "its") so that when I type the word it inserts itself and is not auto-corrected.