Maybe all the features still missing in the Android Firefox played some role ?

Stuff like no print support, no keyboard shortcuts or no tab-bar on tablets ?

Not to mention general extensions support being a shit show as well, with basically just a very small curated list of extensions (mainly add blockers) being supported out of the box.

All of these features were supported by Firefox on Android until ~2 years ago, when they did a rewrite and then ignored requests to bring this functionality back ever since.

A couple links to the Android Firefox open issues:

keyboard shortcuts - https://github.com/mozilla-mobile/fenix/issues/3729

print support - https://github.com/mozilla-mobile/fenix/issues/10217

tab bar in tablet mode - https://github.com/mozilla-mobile/fenix/issues/2344

tablet UX improvements - https://github.com/mozilla-mobile/fenix/issues/4498

I switched to Iceraven [0] last year and never looked back. It is a fork of the new Firefox for Android but with a much longer list of extensions and about:config support. I specifically need the latter to route traffic through a local proxy before.

[0]: https://github.com/fork-maintainers/iceraven-browser

Oh and it is written in Kotlin. Maybe I should learn it just to try hacking more features in.