When I try to hold the button on the DP input option, it immediately switches the input and the OSD menu vanishes. However, I can not change this setting for the DisplayPort input. I can successfully do this for the TB input via OSD by holding down the button for 8-seconds while the input is highlighted. One troubleshooting tip I have tried is to change the default DP 1.4 version to 1.2. I can successfully get the full set of scaled resolutions - of which I use 3840x1620 60hz (scaled down from native 7680 x 3240). I have a 2019 MacBook Pro 16' which does work TB>TB using the Dell supplied TB4 cable. TB 3 > DisplayPort - the display will not detect input ( using this cable).TB 3 > TB - the display will not detect input (using Dell supplied TB4 cable).HDMI > HDMI - this will display at 5120x2160 but only at 30hz (which is expected).What has worked (mac output > monitor input): One display with 5120-by-2880 resolution at 60Hz connected via Thunderbolt 3 plus one display with 4096-by-2160 resolution at 60Hz connected via HDMI 2.0 This should be supported from Apple's documentation: My goal is to get my 2018 Mac Mini to display in 5120x2160 at 60hz on the U4021QW display.
