I’ve always found it simplest to think of privilege as exactly equivalent to well-being.
If all you know about a person is that they are white, then sure, they have a higher percentage of having a more happy, pleasurable, delightful life than a non-white person. If that’s all you know about them.
But if it turns out that the white person does not, in fact, have an enjoyable life at all, then what good was their white privilege? Although certain privileges may be useful when making predictions about the future, when looking at the past, these individual predictive privileges are not worth considering.
Rather, we should just consider the overall happiness, pleasure, and delight they had in their life.
For example, did Anne Frank have a pretty happy life prior to the whole Nazi thing? If so, great, she probably had more privilege than a kid who died of leukemia at age 10. But she also probably had less privilege than any middle or semi-middle class American adult of today. But still maybe more than someone who makes it to adulthood, but has been homeless or for whatever reason miserable for their whole life.