I recently bought a MacStudio with 512GB of RAM and connected it to a LG 5k2k monitor. For some reason there was no way to change the font size (they removed the text size "Larger Text ... More Space" continuum from the Display section of settings) so I ended up with either super small or super large fonts without anything in-between. In the end I had to install some 3rd party software and mix my own scaled resolution with acceptable font size. This has never been a problem on Linux in the past 10 years, all I needed to do at worst when it wasn't done out of the box was to set scale somewhere and that was it.
I bought a MacStudio 2 months ago, on Sequoia you go to "display" and should see the various resolutions. If not, "advanced">"show resolutions as a list">"show all resolutions".
Unfortunately, resolutions offered were weird. Native is 5120x2160 but that wasn't offered and scaled resolutions were weird. I guess macOS didn't read monitor's information properly or something. I wasted a few hours frantically trying to figure out how to connect a $12k computer to a 4-year old monitor which should have been a breeze but for some reason wasn't. The same monitor worked fine on Linux or Windows.
I feel like this has something to do with Apple fucking with DP 1.4 for the ProDisplay XDR.
My 2019 Mac Pro with Catalina could happily drive 2 4K monitors in HDR @ 144 Hz.
People wondered how Apple got the math to work to drive the ProDisplay.
Big Sur? Not any more. 95Hz for 4K SDR, 60Hz for 4K HDR. Not the cables, not the monitors. Indeed, "downgrading" the monitors advertised support to DP 1.2 gave better options, 120Hz SDR, 75Hz HDR.
And it was never fixed, not in Big Sur, Monterey or Ventura, when I had switched monitors.
Hundreds of reports, hundreds of video/monitor combinations.
Frantically? For hours? If that is what you meant, did you try stepping back for a few minutes, and coming up with a plan / doing research?
BetterDisplay has solved a ton of problems like this for me; when MacOS gets confused about non apple monitors, BetterDisplay knows how to fix things.
Curious what software; I've used "SwitchResX" in the past and it met all my needs...
AFAIK the smallest 5K2K is 34", with a PPI of 163. I don't believe that is treated as "HiDPI" by macOS, is it?