Well, most extensions seem to work great already. But that requires using either Nightly Firefox (and some hacks) or using a fork (like Iceraven) that loads a different extension list.
So, it's easier to switch to browsers like Kiwi Browser (privacy concerns aside so be cautious!) if you want a better extension support experience. Bromite and Vivaldi also have great built-in adblockers but sadly no full extension support.
So, I dropped Firefox on all my devices and moved to Vivaldi + Kiwi Browser and that works like a charm.