Yeah, perhaps the video doesn't showcase it, but it actually just comes back after a second, regardless of if I move my mouse or not.
No it doesn't, it just sits on the screen, if you have emails there it goes to that corner, then disappears after a second. It just jumps around appearing/disappearing as I go through stuff. Very annoying, but not actually blocking functionality.
Nope, it just tells you some basic privacy info, wants you to link a Google account, wants you to change your account emails for different services (you have to click done on them all) and wants you to login on their mobile app.
It seems like this was their plan for adding the extra 5GB storage to free accounts, which I think is fair, if you are not forced to link a Google account, that's the worst offender here. It appears massively bugged though and probably should not be appearing on paid accounts at all.