Has anyone gotten the Apple 27" Studio Display to work with Mojave?
It might work for 4K. I think DSC is supported in Catalina but not Mojave therefore it will need to be connected using Thunderbolt to get 5K unless you can get 5K to work with a custom timing at lower refresh rate (somewhere between 39Hz and 47Hz). Actually, the Mac mini 2018's iGPU doesn't support DSC and width > 4K for single tile (single DisplayPort connection) is only supported in Big Sur and later
#1 . An eGPU can do DSC in Catalina and later and can support width > 4K.
With Thunderbolt, to get 5K60 (uses dual tile mode using two DisplayPort connections over Thunderbolt), you may also need the Apple Studio (ae3a,ae3b,ae3e,ae3f) override files from Monterey or later macOS versions (override files contain scaled resolutions, display-rotation-policy, display-contrast, mtdd, denylist). I don't think anyway has tried this though?