There are a handful of options if you’re looking for a tweaked version of the YouTube app (no jailbreak needed) with enhanced options (blocking ads, skipping sponsored segments, allowing downloads, enabling PiP)
I personally use YouTube Reborn Plus https://github.com/arichorn/YouTubeRebornPlus
As for loading the IPA onto my iPhone I use Sideloadly. https://sideloadly.io
I know a lot of others use AltStore. https://altstore.io
Keep in mind, if you have a paid Apple Dev account like myself you only have to load the app on your device once a year. But, if you have a free account you’ll need to do this weekly. That being said, that is why so many users prefer AltStore, it automates the process to ensure you don’t hit that weekly threshold.
If you relate to the guy on the bottom you won’t.
🎵Sweet Beans (Are Made of This)