Operating System: Kubuntu 20.04
KDE Plasma Version: 5.18.4
KDE Frameworks Version: 5.68.0
Qt Version: 5.12.8
Kernel Version: 5.4.0-29-generic
OS Type: 64-bit
Processors: 8 × Intel® Core™ i7-6700K CPU @ 4.00GHz
Memory: 31,3 GiB of RAM

I have an 1080p and a 4k monitor. Sadly there is no automatic scaling so I tried to use xrandr to fix the problem. I set global scaling to 200% and used
xrandr --output HDMI-0 --scale 2x2 --mode 1920x1080 --fb 7680x2160 --pos 0x0 && xrandr --output DP-0 --scale 1x1 --pos 3840x0
as far as i understand this basically makes the 1920p monitor render as a 4k screen which then the monitor downscales again.

I wouldn't call this a solution and more like a workaround. Also the quality suffer by doing this as the monitor has to downscale.

Another problem i ran into is plasma not adjusting the desktop to the new size. So a restart of plasma is needed too.

What is the intended solution for this? I ran into multiple older forum posts which all lead to no results. I mean windows can do it easily...