AMD Ryzen on Linux is still a work-in-progress. "Does not work" is not great problem description, so perhaps you can share a debug-enabled kodi.log file in Milhouse forum thread on Kodi Community Forum .
It's worth pointing out that the Linux kernel currently has no HDR support. It is active "work in progress" from Intel, albeit rather slow progress due to the large number of other drivers (and companies with commercial interests) that will consume the same changes once merged (so lots of cooks in the kitchen sharing their opinions). One of the component patch series' is now on it's 17th iteration so things are hopefully nearing a conclusion.