Dell U4021qw connection through HDMI to Mac M1

I got the new Dell U4021qw working over its TB connection with my Mac M1 at full resolution 5K2K. Had to use my own TB4 cable since the Dell TB cable that came with the monitor was not working properly for some reason.

However, I want now to drive the monitor through an HDMI connection (so I can drive a second monitor over TB) but Mac M1 does not recognise the display's 5K2K resolution when connecting through HDMI. Monitor clearly works fine over TB so it seems the problem being with Mac M1 not able to detect all monitor modes when connection over HDMI instead of Thunderbolt.

Any solutions to this? Is it an OS issue? I tried SwitchResX and other utilities but the 5K2K modes are not listed in there. My PC connects fine over HDMI in full resolution so issue seems with Mac M1 only.