Scaling is broken for any device with a different DPi than a PinePhone
Plasma Mobile by default has scaling set to 200%. However on for example a SHIFT6mq that is tiny.
A scaling somewhere between 250% and 300% would be way better. I think my preference would be 300%. However the the higher it's scaled the uglier things will look; fonts, icons, everything is becoming slightly blurry and not as sharp as it should be.
The most "broken" thing however is that even with a custom scaling set, that won't be applied on a reboot till after the unlock sim dialog is gone. So you have a tiny screen unlock and a tiny sim unlock dialog to go through before it'll scale back to the custom value you've set in previous reboots.
This all occurred for me on the SHIFT6mq, but in reality this happens to any device with a screen DPi other than what the PinePhone's have.