They also don’t allow you to install Windows executables. They do allow you to run adblockers designed for Safari, like Wipr, and there are any number of noscript-alikes, like StopTheScript. I’m not saying that to be snarky, but to say that different platforms have different ways of doing things.

And Firefox is in the iOS App Store. I know what you meant to say, and that it’s not the same as Firefox on Android, but it’s wrong to say you’re not allowed to install Firefox.