FWIW, I'm using GrapheneOS specifically to de-Google (in the sense of them vampiring my data). I've tried all the open source keyboards and they are all unusable for me. I am running the latest version of Google's GBoard which is the best keyboard for me functionally by many miles.

The beautiful thing about Graphene is that you can install GBoard and very simply give it zero permissions; no networking, no contacts, no microphone, no photos and videos... and then you get a fully functional keyboard and none of the siphoning.