Both dynamic range and gamut are well defined terms.
High(er) dynamic range,m and wider(er) gamut are basically the same, but in different directions...
Scene image (having colours beyond Rec709 gamut) is not an issue, as if the camera can't capture all the available gamut, it will clip.
This really happens in the real world - just with colours such as neon signs, and similar.
Low bit depth can be an issue in any image format!
To use 8 bit on ANY high dynamic range, or wide gamut image, will exasperate the issue, and potentially cause banding type artefacts.
Mob Boss at Light Illusion