From the new terms:
When you upload or input information through Firefox, you hereby grant us a nonexclusive, royalty-free, worldwide license to use that information to help you navigate, experience, and interact with online content as you indicate with your use of Firefox.
That’s still Chromium though.
Same, though engine diversity is also a huge factor. I actually used Opera until they abandoned their rendering engine, and then went back to Firefox.
When Firefox doesn’t cut it, I use Brave with the crypto BS disabled. It has a great ad blocker and is just as good as other Chrome browsers at compatibility.