Using qutebrowser I have noticed an issue cropping up:

If i play two videos simultaneously in two different windows and move one of those windows to another workspace/tag the performance of the browser reduces to to about 1/fps. Audio plays without any issues.
This issue persisted with kde-falkon, which is why the maintainer of qutebrowser redirected me here. (https://github.com/qutebrowser/qutebrowser/issues/6551)
I've attached a webm demonstrating the issue.

I'm running dwm, which does not use Wayland. (I've seen similar bugs which were specific to Wayland)

Let me know what other information you require to reproduce this bug, I'll be glad to help.