Thank you for this inspiration, I've created my monthly payment now. I cannot imagine being forced to use anything else than Firefox... (Even though the Android version is barely usable after the rework...)
Oh, I use it as my daily driver mobile browser. And I agree it has improved quite a bit (so that it is now usable, though with a lot of bugs/missing features/inconsistencies).
It's compatible with many add-ons missing from FF on Android and has some additional features that were "lost" in the Fenix release.
https://github.com/fork-maintainers/iceraven-browser