I see no reason to use any other browser than Firefox and maybe Librewolf.
Firefox on desktop is awesome. Firefox on mobile is painful.
Android firefox is ok now. Moreover now it supports add ons too and there are some good add ons there.
It’s a very small number of add-ons, but one of them is uBlock Origin, and that’s all I really want.
You can just change the list of supported add-ons to whatever you like.
Only if you tie your browser with an account at Mozilla. No way to do it without an account.
Only if you need your list. Otherwise you can just switch the list I’d to one including your extensions