Blame Apple for that, as for the longest time they only allowed using the Safari engine on iOS. Apparently that's still the case outside the EU now, meaning Mozilla would need to maintain two versions on iOS.

On any other operating system, Firefox is by far the best at blocking ads with uBlock Origin.

Apple limits mobile browsers a shit ton. When you get Firefox on iOS, you don't get Firefox, you get what's basically a safari front end. This is the reason you can install uBlock Origin or other extensions on the android version of Firefox, but be unable on the iOS version.

Yep, I wish Firefox stepped up in this matter, since their competition can implement decent adblockers on iOS, while dealing with the exact same limitations Apple has set.

On iOS the Orion browser lets you use Firefox or chrome mods.

Just install AdGuard. Works great.

Or rather,... iOS isn't

Install uBO?