I usually watch YouTube through apps like PipePipe or NewPipe. I’m currently watching a series about a video game and one of the parts is age restricted (probably because of some mild nudity).
In the past the solutions have been easy in the rare cases I have been hit by this. Changing your country through a VPN or, updating the 3rd party client apps or using a random YT Download service usually worked. This time it seems like the changes affect the API of YouTube.
Is there a currently working way to watch age restricted videos without creating a Google account?