From the new terms:
When you upload or input information through Firefox, you hereby grant us a nonexclusive, royalty-free, worldwide license to use that information to help you navigate, experience, and interact with online content as you indicate with your use of Firefox.
Just use something else on mobile. I use mull (until it becomes insecure because I think they stopped working on it) and fennec.
Fennec supports extensions and syncing so it should be okay for most use cases.
IronFox is a fork of Mull when you decide it’s time.
please consider switching to ironfox, it’s a mull fork
I need sync…
https://www.xbrowsersync.org/
You can selfhost it too.
Fennec and Librewolf support logging into a Firefox account and thus sync. However, that obviously partially brings you back to the Mozilla problem…