@[email protected] i found today 3-4 other persons having same or similar issues (one on the bugtracker github of systemd and 3 others on the archlinux forums) starting around the same time (in the last 2-3 weeks).
I dont think its Plasma related (which comes in later on boot I think) but maybe Kernel based - since others started having similar issue around the same time?
Might be related to some usb devices, but if i‘m not alone having it!?
It is related to the Samsung screen. There‘s a kde bug since Plasma 6.2 where this is happening. Long story short: disable ddc (look up your plasma-powerdevil.service file (mine was in /usr/lib/systemd/user) and add Environment=“POWERDEVIL_NO_DDCUTIL=1” to it. Save, restart powerdevil (or reboot) and it shouldn‘t happen anymore.)
See https://bugs.kde.org/show_bug.cgi?id=494522 for reference. Hope it works