I use Firefox and also got that pop-up. Eventually I just grew tired of clicking the “X” button so I went on uBlock origin and added that stupid banner and the banner background to the blacklist.

It’s like nothing ever happened. And if shit continues to get worse, either someone comes up with a fix somehow, or I’ll just find a way to run ReVanced YouTube apk on my pc or something. I don’t care if I have to emulate it somehow.

Also, on mobile GrayJay is a good alternative to ReVanced. Made by LouisRossmann’s team apparently.