Just updated to the new version:
Versiune Opera One: 131.0.5877.5
Versiune Chromium: 147.0.7727.56
Nothing changed. The problem is still here.
After update, the promo says:
What’s new in Opera
Now watching videos in Opera is a whole lot better.
Video Popout
Detach online videos into their own adjustable, movable, floating window. YouTube, Netflix, Twitch, football streaming sites - almost any video provider.
With Opera, start a YouTube video or any supported online video, and a new button will appear at the top center. Click it to open the video in a smaller popout window.
The button appears in the top-center when you mouse over an online video.
You can resize this floating window and place it anywhere on your screen.
You can move it wherever you want, as well as adjust the size.
The popout window has its own controls, letting you pause, close it with one click, or return it to the original tab.
Unfortunately, there is nothing "a whole lot" better. Or even true:
the main video in page has no such button at the top center for detach the video (when mouse over the video)
the video popout opens by himself despite the fact that this feature is disabled in Opera settings
the video popout appears in the lower right corner of the page and it cannot be moved or resized
the video popout has no controls to return it to the original tab
So, I think that it is a lot of work to do to make this promo to be real.