I still have one niggling worry about using ultra-high resolution displays for post-exposure photo-processing.
If I process an image to what I think looks "best" on such a screen, is there not a danger that a competition judge, using a "normal" monitor to assess my entry, will see a poorer image than I saw on my super-duper screen?
Yes. But that also means you are not using targeted output sharpening. The optimal sharpening may differ (from somewhat to a lot) depending on the final output resolution (measured in angular resolution, so also viewing distance dependent).
It is not possible to produce optimal output sharpening for multiple viewing conditions, but one can try and optimize for more than one situation. Images also do not become suddenly crappy when viewed at a slightly different angular resolution than where it is optimized for, so there is some leeway.
You can use the first section of my (DoF) Output Quality Planner
tool to get an idea as to what to look for. When e.g. the viewing distance and output size of the display is entered as intended output parameters (assuming full image viewing, not pixel peeping), you will get an indication of the actual PPI resolution of your source data at those dimensions.
If your source data has e.g. 4x the PPI potential at the actual display dimensions, then one can divide the 4x oversampling potential by 2 and get the radius required for a High-pass output sharpening pass that boosts all relevant spatial frequencies at the display size. Smaller radii are not very effective, larger radii will affect larger structures.