Issues with multiple displays and resolutions

I know fractional scaling is a bit of a pain point for many DEs, but I was wondering if anyone was able to come up with a convenient solution for a setup similar to mine.

I have two monitors:

  1. Primary 2560x1440
  2. Secondary 3840x2160

Which looks like this in the display configuration:

What I want is to have my primary display scaled to 100% and my secondary display - to 150%.

However, my current issue is that after a system restart Plasma seems to scale UI according to my secondary 4k display, which results in a comically large UI for my main display, even though the secondary display isn’t scaled at all due to global scaling set to 100%, which makes everything too tiny.

The way I work around this is by unplugging the secondary display before starting the system, then booting in Manjaro where everything is now scaled to the primary display, plugging the secondary display again (thus keeping the original UI scale), and scaling the secondary display output up via xrandr.

I’ve looked at HiDPI - ArchWiki and cscs / hidpify · GitLab but wasn’t able to find a solution to my particular problem. Has anyone found a way to solve this?