Interesting, besides the noted power mode addition, firmware V034 also changes the HDR tone mapping setting to actually have an effect on the image now.

The 3 settings now show noticeable differences in luminance whereas on V024 all 3 settings where basically identical. The ASUS Gaming HDR and ASUS Cinema HDR settings now clip at around 900 nits, with the Cinema mode showing some roll off just before clipping. The Console mode keeps the same behavior as the previous V024 settings, clipping at +600 nits.

So now I actually have a reason to switch from the default Gaming HDR mode to Console mode, since both XSX and PS5 have HDR calibration built in at the system level. I'll probably leave it in console mode as long as whatever content I have displayed on the monitor has HDR calibration settings. The only reason for me to switch back to Gaming HDR would be if I had something connected that isn't aware of the 600 nits peak brightness, like video from a Chromecast.