I don't recall exactly when it started happening, but I've been having lots of issues with recent iOS versions rewriting not the last word entered, but the word before that. For example, if I start entering "I went to", it'll sometimes correct to "I want to", but it'll do that after I've typed the "to". I've found lots of similar examples. The retrospective nature of the edits mean I miss a lot of them and makes me appear a lot less literate than I am.

Same happens to me quite very often on a mobile, even here. But I use iPhone SE 1st Gen. with iOS 15.8.

Transformer based autocomplete on iOS 17 feels just as bad -- but in different ways -- as its previous incarnation to me.

Are you tapping the keys or swiping over those that make up the word you want to type? In my experience, tapping has always been and remained poor but swiping is getting better and better with every iOS version.

Swiping through keys doesn't have anything to do with autocomplete. Autocomplete has to do with predicting which word you're going to type next, not guessing which word best corresponds to the swipe you just made.

Those are very related tasks, you use results of the former to help you with the latter.