Not even speaking about all the ads in the default YouTube app without a subscription.
The app is basically useless in my opinion. It defaults to freaking 240p for every video. My phone is definitively not the problem, also not the Internet connection. Watching in Firefox on the same connection gives me normal expected quality.
This was better on some “feature phones” without touchscreen!!! YouTube app works and playback is in 720p / 1080p
Go with Invidious. inv.tux.pizza works for me when I’m on a browser. (I swear I’m not affiliated with them 😅.) On my desktop and laptop, I use FreeTube because it allows me to track my watch history and subscriptions locally, and it has Sponsorblock and DeArrow optionally integrated. Plus, it’s just nice to separate YouTube, which I often watch like TV, from active browsing tasks. On mobile I typically just use Invidious in Firefox.