RE: Set up 4k HDR External Monitor Output for Dell Precision 7720??
You can try installing drivers directly from NVIDIA, although I don't think that will change anything. Do you have an external display actually attached when you're checking for color settings? The "Graphics special mode" does not cause the dGPU to take control of the built-in panel, so if that's the only display active when you're looking in the NVIDIA Control Panel, that might explain why color settings are missing.