Google is in the process of undermining the effectiveness of uBlock Origin and other adblockers on Chrome and other Chromium browsers. I believe that change comes into effect this year.
But even before those changes were announced, uBlock Origin’s creator and main dev has stated that uBO is most capable on Firefox.
All iOS browsers have to use Webkit (or did last time I checked). So there's not much of a point of running Firefox on iOS. It's basically the same browser no matter what browser it says it is.
I still firmly believe there is at least one sane engineer there who'll discourage this, knowing this will drive the last few tech-savvy users and their family members and close friends away and I will die on this hill