As an iPhone user I like to use YtLitePlus, it’s pretty much the same user experience as using revanced on android, maybe even a bit better. I’d like to have an alternative client such as NewPipe but hey, we can’t have everything.

You can also patch YouTube in a similar way as revanced on iOS, I use YTLitePlus. And for Adblock I use the Wipr extension and hush for blocking and auto rejecting cookie popups. No jailbreak needed.