Mozilla is unhappy because the use of browser engines other than WebKit will be restricted to the EU, forcing them to develop two different apps.
For an independent browser like Firefox, managing two browsers is not easy, so it can be forgiven that this could be seen as almost harassment.
Also, the fact that the use of browser engines other than WebKit is limited to iOS means that the use of WebKit is still forced on iPadOS, which also increases the effort for Mozilla.
I use DNS level blocking for blocking ads on iOS devices.
Yeah not comparable. There is so much cosmetic blocking and also many sites will just load ads from the same domain.
Like YouTube iirc.
Which service do you use (if any) for it? Personally I use controld but I hear NextDNS is the most popular