PopOS is Ubuntu LTS so it’s only getting ancient KDE Plasma and no, not worth it.

Aside, yes it’s fairly easy, but you might need to change couple of settings regarding theming and then roll back to defaults to un-fuck some desktop theming.

The problem isn’t reproducible without the display cloning to your Elgato capture card, right? Could you try a different compositor like Sway, Wayfire, Hyprland or cosmic-comp? If it works well there, you could report issue on https://bugs.kde.org/ in kwin project.

Can you clarify what graphics driver do you have in use currently? Dunno if it’s kwin_wayland problem or a driver problem, but wonder if it isn’t on NVIDIA