HiDPI scale issue

Hello and thank you for reading my issue. I appreciate this might be the 1000000 time someone write about this issue, however, after several attempts and reading I’m still unable of making this to work.
My external monitor is a 4k monitor, whereas the laptop monitor has reguar dpi. Many apps works just fine, such as the new installed ones, firefox, chrome etc. Nonethe less, apps such as yast, dolphin and kate have a weird behaviour I am attaching a picture to illustrate my problem.
I dont care about scaling, in fact, I would like to keep the scale = 1. Everything looks normal at my “lowDPI” monitor, but when i open the apps in the HiDPI, all the menus, icons and letters get huge and many time intelligible.

What should I try?.. I played with the environment varibales QT_AUTO_SCREEN_SCALE_FACTOR and QT_SCREEN_SCALE_FACTORS… still no joy. Any clue?

BR, Ariel

https://imgur.com/a/DE1qwLA
https://i.imgur.com/p8ExYwW.png

You could try using xrandr to scale and pan the HiDPI display image as described here

https://wiki.archlinux.org/index.php/HiDPI#Multiple_displays
and also mentioned in this thread
https://unix.stackexchange.com/questions/204118/xrandr-issue-when-panning-second-monitor#217715

If you can get the xrandr configuration providing the output that you desire, it can then be made persistent by executing the command via KDE’s ‘Austostart’ function so that it takes effect after logging in.

System Settings > Startup and Shutdown > Autostart…