SUMMARY
In HDR Mode, when refresh rate is changed from native 120 Hz to a lower refresh rate the color depth gets lowered too. When in 120 Hz the color depth looks the same as when running Windows (10 Bit). With 60 Hz it looks like 6 Bit color depth.

STEPS TO REPRODUCE
1. HDR enabled and monitor set to native refresh rate
2. Lower refresh rate to something like 60 Hz 

OBSERVED RESULT
Really bad color banding, looks like 6 Bit color depth.

EXPECTED RESULT
Same color depth as native refresh rate, in this case it should be 10 Bit

SOFTWARE/OS VERSIONS
Operating System: CachyOS Linux 
KDE Plasma Version: 6.1.5
KDE Frameworks Version: 6.5.0
Qt Version: 6.7.2
Kernel Version: 6.10.10-2-cachyos-lto (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 5800X3D 8-Core Processor
Memory: 62.7 GiB of RAM
Graphics Processor: AMD Radeon RX 7900 XTX