SUMMARY
When alt-tabbing away from a fullscreen game (run via Steam Proton in xwayland), the focus on the taskbar switches to the application I tabbed to, but the fullscreen game remains "on top" of the application I switched to. I have to change focus to a 3rd application, then back to my initial target for it to appear.

STEPS TO REPRODUCE
1. Download and run a fullscreen game from Steam (In my case it's Throne and Liberty)
2. Wait until the game is fully loaded
3. Try to alt-tab to another application (e.g. a browser)

OBSERVED RESULT
Focus switches, but the newly focused app does not appear "on top" of the fullscreen application you switched away from.

EXPECTED RESULT
Focus switches, AND the newly focused app appears on top of any other applications.

SOFTWARE/OS VERSIONS
Operating System: CachyOS Linux 
KDE Plasma Version: 6.2.0
KDE Frameworks Version: 6.6.0
Qt Version: 6.7.3
Kernel Version: 6.11.3-3-cachyos (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 3700X 8-Core Processor
Memory: 31.3 GiB of RAM
Graphics Processor: AMD Radeon RX 7900 XT