i had altstore with a modified youtube ios that had adblock and sponserblock. It was annoying to keep alive since altstore required a refresh every 7 days with a PC.

Currently I am using youtube on iOS safari with adblock extensions on safari and that does the trick for me.

Pro tip: if you want PiP on safari ios for youtube. You have to go fullscreen then swipe for Home Screen. That will also enable background play for safari iOS youtube. Otherwise YouTube script will pause the video.