PSA: For folks looking for a swipe enabled keyboard on GrapheneOS without using Google's gboard, try Heliboard - https://f-droid.org/packages/helium314.keyboard/. It's 100% FOSS, but can also use the binary blob from google's gesture typing library "swypelibs" to provide swipe typing. Since helium can't access the internet, I am okay with that.
Also try the Urik Keyboard APP from f-droid
There's also FUTO Keyboard (https://keyboard.futo.org/). Nothing against Heliboard (I actually don't even remember why I chose it over Heliboard). Just another good option.
I think they recently finished reimplementing the swipe library so now it no longer requires blobs.