Macbook Pro - No HDR option on projector

I have a 2018 15" Macbook Pro with discrete Radeon Pro 560x, running Monterey (12.0.1).

I'm trying to hook up my projector (Optoma Cinemax P2) for 4k HDR content.

Connecting using a USB-C to HDMI cable, I get 4k60 (so HDMI 2.0), but I do not get the option to enable HDR.

The projector only has the option to detect HDR content and cannot be switched to HDR mode manually, which could be causing the problem? Maybe?

Any ideas on what's happening, and how I can sort it?

Thanks. :-)