How many clears are necessary to get to the final ending of Hades?

In Hades, you could consider 1 ending being the ‘clear once’, or the credits ending being the final ending, that happens at about 10 clears.

But on Steam, there’s a very rare achievement, called ‘see the epilogue’. So I guess there’s a ‘final’ ending, but how much clears do you need to trigger it? (Or if the completion is something else, what is the requirements that are needed and, if not too variable, at how much clears do people usually get there?)