Already tried 2022-beta-0.9.0 (not sure if the one I have is the 6000064828).
That's worse. Vivaldi is not supported. See screenshot.
Vivaldi is chrome under the covers,, just like edge is.
Set the user agent override to the latest chrome in Settings > DVR. Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.110 Safari/537.36
I followed your instructions on putting the latest Chrome agent in the DVR settings. That did allow the HBOMax home page to load (it didn't before I did that). But I cannot login (my provider is ATT) and I know my credentials are correct, because when I go to a plain browser and login directly to ATT, I get right in. So somehow, your browser is blocking my ATT provider login on the HBOMax login screen. Screenshots are attached, demonstrating the sequence of events.