The short explanation
HDR10 uses 10-bit color, the BT.2020 container and static metadata: one set of brightness figures that applies to the entire title. It is open and royalty-free, which is why support is universal.
Static is the limitation. A film with a bright daylight scene and a dark night scene gets one mastering figure for both, so the display's tone mapping has to compromise across the whole running time.
Where you run into it
Because it is the baseline, HDR10 is what a chain falls back to when a richer format fails to negotiate. If you were expecting Dolby Vision and got HDR10, that is not a broken picture — it is a signal that the DV capability never made it through.
It is also the right target when you want predictability. Fewer moving parts, universal support, no vendor-specific data block that has to survive the handshake.
How the DR HDMI 8K handles it
HDR10 is one of the explicit options in the DR HDMI 8K's HDR flag, alongside HDR10/HLG, HDR10+ and HDR10+/HLG, and it can be removed altogether. Forcing plain HDR10 is a clean way to find out whether a Dolby Vision problem is in the content, the source or the capability data.
Want to test your own HDMI chain?
The DR HDMI 8K is sold through the HDFury.eu web shop.