Please disregard. Problem solved. Turned out it is my HP USB-C hub that is not passing through the HDR signal. Connecting HDMI directly to my laptop all settings become active. Kind regards. 
Hi, I am having issues with HDR. Even though I change settings to use SmartHDR, the S3422DWG is not recognized in Windows that it is capable of using HDR? I tried HDMI and DisplayPort and none works. Please let me know if this is a known issue or just with my S3422DWG? Kind regards
S3422DWG, Windows not showing HDR