I'm one of the developers of Mister Keyboard. If you want, you can give it a try! Everything essential is completely free, maybe it works out for you.

For something that is as personal as a keyboard, it would be good to know what "Usage data" you are collecting and how it is used. I am eager to switch away from ios keyboard, but I do not trust most developers to have access to what I type. I understand it is "not linked to me", but this is an area where heavy skepticism is warranted.