Most people here focus on autocorrect, which isn't such a big problem for me since I'm used to having it off.
But what the hell is wrong with the cursor placement? It is so incredibly broken, it has a mind of its own, and never goes to where I mean to put it.
Simply tapping on text puts it in the wrong places, but holding and dragging cursor or holding and dragging on the spacebar to move it also works terribly, somehow it never does what I need it to.
Selecting text is just as terrible.
It's also impossible to put the cursor in the middle of a word. WHY NOT? Just put the cursor where I tap! It is so easy to do on Android.
I find it much easier to type and move cursor on my Galaxy S9 than on my iPad mini, despite the iPad having a much bigger screen.