You can get close by:
Save to Rec2020 linear TIFF (darktable can do this easily, I need to dig into how to do it in RT)
Encode that linear TIFF to a 30-second 10-bit H.265 stream with an HLG transfer curve and appropriate HLG metadata.
Doing so looks AMAZING on an HDR-capable display. But encoding stills to 30-second videos (which compress well since the predicted frames all say “no change”) is a really horrible way to deliver stills to an HDR display - but since most HDR TVs don’t support HEIF there’s no other way to display stills on an HDR display and have them trigger HDR mode.
This weekend I’ll try and dig up one of my old example ffmpeg command lines from last year, they’re on my old laptop and I haven’t transferred a lot of documents over.