Youtube is trying things again.
Switched to #bravebrowser! That was it.

@liagason I get the same pop-up in brave, you might just have gotten lucky A B testing

I assume you didn’t copy over your cookies but re-logged-in

@lil5 I logged in again, yes. I'm on the default #bravebrowser settings, and I'm also using the #duckduckgo extension. So far, it works fine that way.
FreeTube - The Private YouTube Client

FreeTube is a feature-rich and user-friendly YouTube client with a focus on privacy.

@lil5, thanks! I just installed it. It looks really promising. I think the fact that it's not tied to your google account is a huge plus.