I'm a FF user since the early 00's and Firefox will mostly not go away because Google has an interest in using it against monopoly accusations but the reality is bleak..
And the reality is these people ( Google in this case ) are so far removed from any moral compass about the Web ( at least what most people here think of "the Web" ) that it's near impossible to do anything about it. These companies are huge and from top to bottom there are certain groups that are hired guns to do a job, no matter what "job" it is, they'll do it, achieve those KPIs, get promoted, get paid. Even for their own detriment in the future, it doesn't matter. Big money now, screw the rest.
Btw, this is how every big company operated since forever, the only "news" here is the disproportionate impact their acts do to the World due to their huge size and influence.
Making FF more prominent will not give Google more power, it will give Mozilla more power to negotiate better deals with Google and Bing to become the default search engine, because in the world of browsers, that's what pays the bills.
Giving more power to Mozilla hinges on them having a larger user-base so their voice is heard on these technical issues.
I'm tired of people complaining about how much better they could do "if only" this, or that FF was % slower on some tasks 10 years ago.
Firefox is a better alternative. It's the only alternative, and we can make more demand on its direction if we actually use it.
It doesn't mean that we shouldn't hold Mozilla to higher standards, but if we keep waiting for them to be perfect before we will consider using and pushing FF, we're just going to lose the only alternative not controlled by Google or Microsoft.
It's Firefox here and now. There probably won't be a tomorrow otherwise. Google is making that very clear.
About the only use case I still need Chrome for is for sites requiring experimental web APIs not supported by Firefox, such as Web USB or Web Bluetooth. Site compatibility for everything else, including very heavy web apps, is just fine.
History sync is encrypted, which is what made me switch over in the first place (Chrome deactivates history sync when activating end-to-end encryption – go figure…)
The only site I have compatibility issues with on desktop is MS Teams and even then it's only for voice/video calls, everything else works fine.
Firefox Android is a slightly less happy place. The password manager doesn't work very well (am moving away from the built-in one) and I can't log in on Amazon (which is important because I can't buy Kindle books in the app because of the Play Store).