[waydabber]

You can simply create two dummies and mirror each one to separate displays. Or you can use the 4K display as is (since it will natively have 1920x1080 HiDPI on M1) and create a dummy to use with the QHD display to get 1920x1080 HiDPI.

[lxgr]

I guess, but my point is: There is no reason macOS shouldn't allow doing all of this on the software level.

Especially with the wholly Apple-made M series of chips, they control the entire video stack down to the transistor level.

Dummy plugs should be syscalls, not physical things.

[waydabber]

Yep, sorry, I guess I was clicking the wrong link while trying to respond to something else.

I agree with you, it is funny that we need dummies and workarounds (being hardware or software).