To think it's fans wanting "more" misses the point. This is the result of diehard fans reading continuation errors, plot holes, and uneven writing with the most good faith possible take on it all.
That being said, any hope of a secret episode was delusional. Netflix doesn't spend a decade and this much money per episode to unlist a True Finale.
I'm somewhere in between on the whole thing. It's a fan theory, and a great one. That's it.