Another vote for uBlockOrigin here

Not rooted, and this is the best option. Tried Blokada and it was just frustrating to use.

You're absolutely right, thanks for catching this. Firefox' addon system is a real boon and the solution that works if you can't/don't want to root.

Before that I was getting frustrated by filtering pseudo-VPN apps and rooting is not an option anymore (sec-wise and because of Google SafetyNet).

Firefox Mobile is dropping extension support for awhile: https://github.com/mozilla-mobile/fenix/issues/574

Firefox Mobile will continue to be Fennec in the short-term.

>when exactly is fenix supposed to replace fennec as Firefox for Android? Once the MVP is done, or when it reaches feature parity?

>We are currently finalizing the transition plan, however we know that Fennec will not be replaced for the MVP, we will make sure our existing users will get the experience they expect later in the year.

If they choose to use an experimental MVP which doesn't yet have feature parity, then sure - they won't have Web Extensions.

Fenix is not the currently supported mainline Firefox Mobile browser, nor will it be for a bit.