SUMMARY
When Firefox is maximized and you have panels in different places with multiple monitors, dragging a Firefox tab to your other monitor does not properly place/maximize the new Firefox window.

STEPS TO REPRODUCE
(prerequisite) Have a Plasma panel on one monitor set somewhere (example : bottom)
(prerequisite) Set a panel on another monitor set elsewhere, different from the panel in the first monitor (example : left)
1. Open firefox and make it maximized
2. Open 2 tabs in firefox
3. Click on a tab, drag it out of the firefox window (does not matter if you drag it from main screen to secondary screen or secondary screen to main)

OBSERVED RESULT
Tab is moved to other screen but the space where the panel should is located from the originating screen is not used.

EXPECTED RESULT
Tab is moved to other screen and is fully maximized


SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Fedora 39 
KDE Plasma Version: 5.27.9
KDE Frameworks Version: 5.111.0
Qt Version: 5.15.11

ADDITIONAL INFORMATION
-Panel size affects the bug
-Bug also happens on Opensuse, it's probably not distro related. 
-Bug does not happen on Windows, it works as expected there.
-Having more than 2 panels on a screen affects the bug (if you have 4 panels on top/left/right/bottom and follow the steps, then the new Firefox window will be reduced by the size of all panels on each side.
-I could not find any other application with a similar tab-dragging behavior to test.