I wonder how true this is now. I believe the functionality in MV3 has increased since it was released. There's still filters that can't be supported, but it seems like most are.

https://github.com/uBlockOrigin/uBOL-home/wiki/Frequently-as...

https://github.com/uBlockOrigin/uBOL-home/blob/main/chromium...

From "ublock-filters" only 1 filter was unsupported and 90 had unsupported domains dropped out of 10436. From "easylist" 18 out of 56109 filters are unsupported, no unsupported domains.

I'm sticking with uBlock-Origin, but not sure how much of a difference it makes these days.