Greasy Fork

Doesnt work with age restricted videos (despite being signed in)

But otherwise only issue besides that is sometimes when loading a video,
its just a black screen with the youtube anti ad blocker text,
but all i have to do is refresh so its still good.

You can unlock age-restricted videos by combining this with this:
https://github.com/zerodytrash/Simple-YouTube-Age-Restriction-Bypass

You should get an unlock button on the age restriction screen. Just click it and you'll be able to watch them.