SUMMARY
This is a very inconsistent behavior that started happening after updating to Plasma 6.5.90, back in 6.5.5 it was consistent and predictable, it is kinda hard to reproduce this, but, I observed this more easily with some fullscreen windows, sometime games, like Minecraft, Overwatch, or even watching videos on Firefox

STEPS TO REPRODUCE
1. Update to 6.5.90
2. Put an application or game in fullscreen
3. Try to open another window from another monitor in the main monitor

OBSERVED RESULT
When trying to open a window from the task manager or with Super + 1, 2, 3 etc... it opens but it doesn't come to the front, it is focused on the back but the fullscreen window doesn't come to the front, and I can see that is working and that is focused with another monitor, I experienced this most recently with Minecraft in fullscreen, I was trying to open Firefox (That was already opened on the main monitor) from my second monitor and it was not opening, after some time clicking it opened for some reason  

EXPECTED RESULT
The application should open immediately after clicking or given the input to, it was like that on 6.5.5

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 6.18.5-arch1-1 Wayland
KDE Plasma Version: 6.5.90
KDE Frameworks Version: 6.22.0
Qt Version: 6.11.0

ADDITIONAL INFORMATION
As I said in the top, this somewhat hard to reproduce, but in my daily use it happened multiple times and it is very annoying, expecting to open a window and it doesn't show up. So, this normally occurs when the window is already opened behind of the fullscreen window, since when you open a wayland app for the first time it pops up on the monitor that your cursor is at, so it wouldn't be a thing