As much as I love Firefox and Mozilla at large, I believe a lot of their woes are self inflicted. Yes, COVID blah blah blah, but a cursory look at their financials shows a NPO that behaved like Goog was gonna continue funding them indefinitely.
Vivaldi is my daily driver on desktop and Firefox is the "sandboxxed" browser. Might start looking into their mobile offering seeing as FF Mobile isn't getting any better. Damn shame really.
On Android, the only thing that the default browser ever opens for is captive portal detection. Otherwise, all links from apps like Signal or OSMAnd open in Firefox. Granted, I am running Lineage OS. Does a phone with Google Play Services installed override Firefox for Android to use the preinstalled web browser instead?
Posting from Firefox on a desktop. I like my Ad Blockers to actually work.