Perhaps creating an account for Youtube only and/or browsing it inside a Firefox Multi-Account Container [1] would already go a long way.
[1] https://addons.mozilla.org/en-US/firefox/addon/multi-account...
[1] https://addons.mozilla.org/en-US/firefox/addon/multi-account...
If you don't have cookies, there are no logins by default. I've been experimenting with this and almost all sites work fine without any cookies these days (as long as you don't need to log in).