However I would also like to point out a facet of the complexity that I have thought about through my own research. And that is the existence of multiple levels of power, privilege, and discrimination, and from looking at all arguments and evidence that I have gotten my hands on, I think is the only sane approach to understanding the reality.

That is, there is both a “horizontal” and “vertical” arrangement of power, privilege, and discrimination systems. The horizontal arrangement refers to the arrangement of the type you are referring to – that between different communities or nations. The vertical arrangement refers to the arrangement of power on each level of organization: community vs. region vs. nation vs. world.

In this sense I would say that a case could be made for a global white privilege or white supremacy in some sense. “White” culture – that is, Western, European culture, sets the standard for all major world institutional designs and all legal systems except those of certain places in the Middle East and everyone tries to assimilate it, and often “progress” involves some form of “Westernization”. All other alternative conceptions except for perhaps Islamic Sharia law were destroyed or repressed into small, isolated communities under the genocidal hammer of colonialism. For white privilege specifically – in many countries foreigners that are White are looked on more favorably than other foreigners, even if they are still excluded to some extent due to their foreigner nature.

On national levels, though, of course, then other prejudices start to appear. E.g. the US is probably a white supremacist nation more or less, but if we go to China, we have prejudices like that of the Han Chinese vs. Tibetans with the former trying to do to the latter what the Europeans did/do to the rest of the world. Neither of these would be considered “White” according to Western racial schemata, and both would actually be considered the same “race” according to those schemata, yet are effectively acting as different races in this Chinese nation. There are other places where the discrimination follows lines that don't even make sense as races, e.g. groups defined by languages.

Going down to the local level, we also would get variation in power/privilege as well. E.g. in the US, which I said was white supremacist at the national level, if we drill in to, say, the local level, you can find Black-dominated communities.

Then there are interactions between levels. E.g. a White person stuck in a Black majority area could be subject in theory to anti-White discrimination from the local majority, yet they would also have the possibility of backup from the broader White-favoring country around them.

Then there is finally the situation – one on one: Person from group A has a gun and you don't. You're in a fight. Person from Group A has mortal power over you, no matter what group you belong to. Bang. You're dead.