Firefox is looking to implement Manifest V3 to keep extension feature parity with Chromium, but their version will not ban the one API that adblockers use. So Firefox will eventually be V3 compliant
Maybe it's my tinfoil hat but if any part of this is related to their google's pursuit of ad revenue, I don't imagine a v3 compliant Firefox will work with adblock for long.
At the very least they would probably make using it a huge headache
I switched to chrome because they were the first to have each tab be it's own process so one bad site/connection did crash the whole program. Also the cloud based password saving across devices was super convenient.
Firefox does both now too, has better ad blocking, and is a little less invasive and bloaty. A lot less invasive if you know how to set it up, which I don't.