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
I've been using YouTube Vanced for years, and now , after Vanced got killed. it's a bit tedious to set up on non rooted phones, but even then, it's such a huge upgrade. no ads, let you pick your own quality, SponsorBlock built in, background play, lots of payout control options.
I remember Vanced being simpler, only making you download the patched app, where ReVanced wants you to uninstall your YouTube updates, find the APK of a specific version, then patch it. not exactly hard for most enthusiasts but still out of reach for most. absolutely worth it though!
I think they technically could, but won't, and never have. using ReVanced isn't nearly as much of a legal problem as Vanced, because ReVanced isn't directly providing modified versions of the official app (which would be redistributing modified copyrighted material), and even then, only team Vanced themselves suffered the consequences, by being forced to shut down. Modifying whatever for your own personal use doesn't come with any copyright issues.
Banning people who use ReVanced would be like banning people who use adblockers on desktop. not only it's not sure if that is actually against their terms of services (they can probably make the argument that ad-less playback is supposed to be a paid feature, and getting it for free is bad), they would never realistically go out of their way to ban everyone who figured out a way to have YouTube without ads. how about browsers with built-in adblockers? how about people who set up adblockers at their router's level, impacting everyone else connected to it?
it's never impossible that they do it, but so far it has never happened. no website has ever banned its users for using adblockers; at most, they would display a popup forcing you to disable it to access the site (youtube actually does that, but said popup is just as easily blocked than ads themselves). considering the huge amount of "what if"s, I don't believe it will ever happen, especially not with no warnings.
the official website is revanced.app . in case of doubt, check https://github.com/revanced. fake websites are sadly always an issue with popular apps that aren't on the main stores