There is, imo, a big difference between having some advantages and having privilege.
A cis m-spec person in a relationship with someone of the opposite gender might have an advantage over a gay person in a relationship with someone of the same gender, but the heteronormativity that causes people to assume they’re straight and the erasure that results is not a privilege.
A closeted trans person might have an advantage over an out but non-passing trans person, but being closeted is not a privilege.
An nb person who is viewed by society as a man may have an advantage over those viewed as women, but having your gender identity erased isn’t a privilege.
If the thing that’s giving the societal advantage also happens to literally be part of the oppression that person faces for their identity… you can’t call that a privilege.