I agree, what I said should not have conflated "rendering engine" with "ability to install fully powered ad blockers". What I meant by that was that Safari's renderer on iOS doesn't allow the full uBlock Origin no matter if you use a reskin of it or not (firefox, brave, etc.), but if Firefox and its rendering engine were allowed on iOS (similar to how it is on android) we would have the full power ad blocker.

It makes a difference. I have uBlock Origin lite on my iPhone and it misses ads on Facebook that uBlock Origin on my PC blocks. Facebook has the most advanced anti-ad-blocker tech, so they're a good benchmark for how effective an ad blocker is.