1) SUMMARY:
After a fresh Debian Stable install I was having problems with Plasma taking longer then usual to end sessions. Logging out, Rebooting, and Shutting Down take about +9 seconds to end Plasma session. I get a black screen but the cursor is still usable.
Rebooting and Shutting Down take +3 minutes to finally take effect. The message I always get is: /dev/sda2/ clean, xxx/xxx files, xxx/xxx blocks

At first I thought it was a graphic-driver issue but its not.
On Debian Bullseye I got two journal errors. One about Pipewire and the other about Intel WiFi card not being "installed". I fixed these issues by removing Pipewire and adding file /etc/modprobe.d/iwlwifi.conf

After fixing these issues I was still having a slow Logging Out sessions. I decided to remove KDE Connect and finally Plasma worked flawlessly as it did on Debian Buster.



2) EXPECTED RESULT:
I have to wait until the next Kernel release on Bullseye to see if it finally fixes the Intel driver bug or if its a bug of KDE Connect.


SOFTWARE/OS VERSIONS 
Linux/KDE Plasma: Bullseye KDE (stable) 
KDE Plasma Version: 5.20.5
KDE Frameworks Version: 5.78.0
Qt Version: 5.15.2