I’ve looked at a few on fdroid and they all seem like they aren’t being maintained anymore.
Edit: I’ve spent the past day trying most all of the suggested keyboards here and I think I’ve landed on either Unexpected Keyboard or AnySoftKeyboard. Thanks for all the suggestions. Thumbkey is quite the thing to get used to.
Idk but you could always just install gboard & not give network permissions. You’ll lose a little functionality like the ability to add gifs from the keyboard which obviously need internet to search/load.