This:
P.S. I prefer the display resolution standard (e.g., XGA, FHD, QHD, UHD) versus the “K” designations. For one reason, it’s (IMO) at least a little less confusing than the other adopted version, which is a mismatch. That is, we went from defining by vertical resolution (e.g., 480p, 720p, 1080p) to categorizing by rounded to the thousand horizontal resolution (e.g, 4k is 3840 pixels).
Maybe I've been confused about HiDPI, but as I understood it, 4k resolution would have a HiDPI display of 1080. Your screen only has 3840x2160 pixels to begin with, why would it upsample to 8k to downsample back to the native resolution? The benefit of HiDPI is the smoothing effect of those extra 4 pixels for every displayed pixel, right?
The OP and some others are confused and/or misusing terms. And because the 2024 Mac mini (i.e., M4) doesn’t support (native) 8k for a single display/monitor — I’m not aware of any Mac that has — then, of course, macOS isn’t going to offer HiDPI 4k/8k. The current best is HiDPI 3k/6k. Also, HiDPI and high PPI (e.g., “Retina”) are not the same.That isn't how HiDPI works. A 4k monitor can not display anything sharper than 3840x2160; so rendering a higher resolution and scaling it down is pointless; the only that *might* do is fake sub pixel anti-aliasing, which why not just bring that feature back instead.
What you really want is a 8k display that renders the UI at 3840x2160 which will be sharper because now it has 2x2 pixels for every 1 pixel to render the same element rather than 1 pixel.
P.S. I prefer the display resolution standard (e.g., XGA, FHD, QHD, UHD) versus the “K” designations. For one reason, it’s (IMO) at least a little less confusing than the other adopted version, which is a mismatch. That is, we went from defining by vertical resolution (e.g., 480p, 720p, 1080p) to categorizing by rounded to the thousand horizontal resolution (e.g, 4k is 3840 pixels).