What is missing to make this depiction of a Black Hole realistic? So i am working on a Music video as a FX Artist and part of the job is a Black Hole. Now i am fairly confident that i am just about the only one on the team who cares how accurat the party is. But i also know that something more realistic will also just look better.

This is the version with post processing (I know the lense flare is like 50 times too big).

And this is the party with out any post processing.
Atm stuff like the lensing and Kerr effect are accounted for (In these renders the spin is 0.5c) But what other effects could be added ? From what i looked up, Doppler Effect may be large but i dont entirly understand it. Is the Doppler Effect related to the viewers position or just the spin ? As in, if i move around the Black Hole does the Doppler Effect change (For example the red side always facing the Camera), or is it static and just in direction of the spin?
I also read somewhere that the entire black hole may look distorted to one side, so it appears as if one side is longer than the other. But i couldnt find anything concret on it.
Also just so we are clear, nobody should be concerned about the realism of the scene as a whole. There will be shadows and god rays so like, just dont think about the fact everyone on the planets would be evaporated.
This is just about the black hole and getting all the effects in.
Lastly, i am not 100% on if the lensing of the background would look like this. As in the 2nd disk around the black hole gets warped as well. In reference images the background, so stars etc, got warped as well but idk.
 A: If you take a look at the paper written by the renderers of the black hole in Interstellar (you might already have), they discuss Doppler shifts in section 4.1.2 on page 22. They also discuss why the hole is shifted to the right due to the spin, although this gets a bit academic. This paper is probably the definitive source on how to simulate black hole visuals, so if there is anything that should be taken into account, they have likely discussed it.

Interestingly they ignore the Doppler shift in Interstellar, using the top picture instead of the more accurate bottom picture. But after Interstellar, your audience might expect something more in line with the top picture.
In general, the Doppler shift of a rotating object relates to the relative velocity between different parts of the object and the camera. The side of the object moving towards you looks more blue, the side moving away looks more red.

Thus, the Doppler shift you see does not depend on the radius or angle from which you are looking at the object. However, if you flip your camera on its head, the object is flipped on its head as well, with the blue and red sides trading places.
Finally, if you orbit the object, the relative rotational speed between you and the object changes. Think of geostationary satellites. From their perspective, the Earth is not moving, and thus no Doppler effect. If you orbit the object at the same angular speed it is rotating, it will appear to be standing still, and thus no Doppler shift. Your rotational speed around it will increase or decrease the Doppler shift as the relative rotational speed increases or decreases.
But in the end, you might just want to go with the Interstellar style rendering, which ignores Doppler shift.
