HDR Content not available on external monitor.

Hello everyone. I am hoping you can help me out.

I just purchased a Mac studio max along with a Gigabyte M32U 4K monitor. The monitor is connected to the computer with a Silkland DP 1.4 to USB C cable that claims it is able to do 4K @ 144hz and is compatible with HDR content. However, I am still not getting HDR content via YouTube. My monitor is set for HDR, my max is set for HDR, but it’s still not happening. What am I missing?? I have attached screenshots of my current settings and the YouTube quality selector that is missing the HDR indicator.

Thank you for your help.