Your system is not up-to-date, as linux61 is now on version 6.1.170-1 in Stable branch.
Also, Stable branch is currently on version 6.6.4-1 of Plasma
So, try updating your system, reboot, and see if the issue still occurs:
sudo pacman -Syu
Also, you might want to try a newer LTS kernel such as linux66, linux612 or linux618 due to polkit issues with kernel linux61 & earlier, as has been mentioned in the Known Issues section of each update announcement since the beginning of this year:
You can list kernels which are available for installation by running:
mhwd-kernel -l
To install a kernel (for example, linux618):
sudo mhwd-kernel -i linux618
After you have installed the newer kernel, reboot. Your system should automatically boot into the most recent kernel version.
Plasma defaults to Wayland now, and you will need to install the plasma-x11-session package if you want to access an x11 session. Note though, that X11 support will be completely removed from Plasma when v6.8 is released in the first quarter of 2027.