That "little graphics scaling performance issue" is due to the Intel UHD-630 graphics chip - it's a hardware issue. The Mini has been criticized for using this graphics processor, and that is why some people use an external graphics processor (eGPU) for more demanding applications.
I think the point is that you want to use your monitor's native resolution, such as 3840x2160 for a 4k screen or 2560x1440 for QHD. That way the graphics chip does not have to work as hard. I opted for a 32" QHD screen instead of 4k for my Mini. Running at the native 2560x1440 resolution, I find that text and user interface elements are a nice size - about the same as 1920x1080 with a 24" screen.
Of course, you can choose whatever resolution looks best and if everything works, then all is good. But using something like 3008x1692 is certainly making the internal graphics chip work harder which causes it to run at a higher temperature.