At work I use Ubuntu which comes with Firefox by default so yeah I use the default.
At home with arch I have to download one anyway ... so I use Firefox.
There has been only a brief period since I first started using Firefox that I used another browser as my main (chrome/chromium back when Netflix only worked on it properly) When Firefox rolled out "quantum" I jumped back never regretted it. Still one of the only remaining browsers.
Smartphones have been "good enough" for a while now. Enough power and battery to do all the things needed for enough time before running out of battery.
IMHO there are 2 reasons we still regularly upgrade.
I've had a few phones over the years some of them I "legitimately" just broke (one had a cracked mb after a bike accident) I broke my second to last phone trying to replace the battery (thought I would be able to, broke the screen). The fact that everything is glued down and made to not be replaceable irked me so much that my current phone is a Fairphone. Replacing the battery takes 1 minute and requires no tools. Replacing the screen takes like 5 min and 8 screws. I plan on using this phone for at least 5 years more if possible. But I understand not everybody can shell out 600 dollars for an "OK" phone.