Google's Web Integrity Android API could kill alternative media clients
arstechnica.com
arstechnica.com
If not, then this has nothing to do with YouTube. Even if Vanced used WebView, I assume it was pretending to be a regular browser, so there is no way the site could require attestation.
However, I can only comment on what Google is actually proposing. In the future, Google could do anything, regardless of whether or not this Android API exists.
"rapid"? It's in line with their lifecycle policy when windows 10 came out.
It seems to me like they are effectively trying to limit your OS choice to one they have sanctioned. What if you want to compile and run your own OS?