As far as something like YouTube Revanced: the App Store rules make it harder, but you can still do it! Check out an app called Yattee, which is fairly barebones—until you connect it up to a third-party YouTube front end for wonderful effect. https://www.reddit.com/r/Yattee/comments/13d3lj7/how_to_set_up_and_use_yattee_to_watch_youtube/