I've never shipped RPF in the typical sense, but a lot of my past fandoms have been historical RPF (Rome, HBO War, Hamilton, etc.) or pseudo-RPF (The Social Network). I still feel a bit weird about it, but in some cases the people have been dead for hundreds or thousands of years so whatever, and in other cases it's a fictionalized story about real people and real events, but I'm shipping how the actor's portray the real people rather than the real people themselves. It's a fuzzy line, especially when it's RPF about people who aren't celebrities.

Though, I should point out that fandom didn't create RPF. It's been around for thousands of years in one sense or another. For instance, almost all of Plato's work is fanfiction about Socrates and a good chunk of Shakespeare's plays were based off real events or real people.