* The laws specify that it must be opt-in. If a site doesn't respect this, you can't expect it to respect any of your choices anyway.

* You can now also use uBlock Origin to set cookies and LocalStorage entries automatically. The annoyance lists already set opt-out cookies for sites like Google and Youtube

* Firefox has actually been isolating third-party cookies and other site data (e.g. LocalStorage) for over a year. It's pointless for you to ever be concerned about them.