This might sound counterintuitive, but it would be really nice to be able to pop a video out using Picture-In-Picture, drag that to a different monitor, then fullscreen it, without having to drag an entire tab (which also seems to duplicate the entire browsing session, including pinned tabs?).
Currently I can take a P-in-P window onto a different screen, but only drag the borders as large as the resolution of the video. Since my monitor is larger than 1080p, the video just sits in one of the corners looking slightly pathetic. Being able to fullscreen that would be great.
I can't be the only person (can I?) that watches a full-screen video on a secondary monitor and have my primary workload on a different one.
I did have this working on an alternative browser - I think it might have been Firefox? But when I switched to Vivaldi (and now Orion), the P-in-P stopped fullscreening and instead was restricted to the resolution of the video, which is sub-optimal.