powerdvd does not support to convert HDR to SDR (which requires color downscaling and re-mapping).
Perhaps the iGPU might do some post-processing for hdr-to-sdr color re-mapping, but generally it will be played as plain non-HDR status.
I think there is no perfect solution on the market currently. The playback result will be pretty bad if you expect you will see the superior quality with 4k disc.
I'm not sure if your 4k blu-ray's hdr can be turned off or not on the movie menu.
If your uhd-bd package includes a 1080p disc as well, the viewing "might" be better than the 4k blu-ray HDR one on your SDR monitor.