If people start from a device they own, then they can actually fight the other battles. Install facebook in a work profile for now but try and get some friends to move to xmpp. Install uber if and only if you're stuck and public transport has stopped for the night (and uninstall it after). Or any other compromise between complete submission and full device ownership.
Graphene as a project doesn't really seem aligned with this idea. Calyx and /e/ are a bit better.