One thing ff can do is make andriod like browser that supports ublock using altstore. That being said, this may not justify the time spent by developer.
Funny you said that, out of the top of my head:
- Brave have a full featured adblock built in on iOS;
- Edge(!) have adblock plus extension built in as well;
- iCab have adblock capabilities built
As you can see, there's plenty of options even with Apple engine restriction. They just don't care enough to give iOS users a good experience, see the frustration on these threads[1][2]. It's all fair, I just gave up using Firefox on iOS and stopped caring about Firefox as well. Surfing the web without a proper adblock is just a rollercoast of frustration.
[1] https://github.com/mozilla-mobile/firefox-ios/issues/7374
[2] https://github.com/mozilla-mobile/firefox-ios/issues/5198