> Keep in mind that tons of website just outright won't work with Firefox mobile

I know this anecdotal but I'm using FF on Android (Lineage OS without google apps/micro g etc. - only F-Droid) and the only site that causes issues is google.com. For some <sarcasm>unknown</sarcasm> reason it servers images in much lower quality. Of course it's not a technical limitation. If you change your UA to chrome everything goes back to normal. That was the biggest reason I moved to DDG.

> it has a very annoying bug that has been known for years where all your tabs will very often reload whenever you switch to another app and come back

I definitely don't have this issue. I have over a thousand tabs opened, it definitely doesn't reload all of them while I'm switching between apps.