I've owned iOS devices since around 2010 I think, and one of the first things I do when setting them up is disable autocorrect and most other typing assistances. For this reason! Also when typing in 2 or 3 languages, it is completely useless.

iOS 18 really fucked up the multiple languages setup. It used to automatically detect secondary languages when I had the English keyboard, but still prefer English. Now you have to create keyboard combos and can't reuse languages (can't "prefer Spanish but also support English" and viceversa)