Mini M4 - External Display No Control Over Brightness

This is my first Mac, first apple product since the first iphone. It easily connected to the HP (527SH) Display through HDMI. Has been working great but I the option to control brightness is greyed out. Why is that and can it be changed or worked around app? If I need to buy a different display, but return window ends today, so.

I am able to change the brightness easily on the display itself but it takes two dozen button presses, its inconvenient and painful.

I have tried different color profiles, and most of the most obvious to a lay person.

Any hope? I really appreciate it.