Refund policy is pretty clear. They make exceptions sometimes but certainly not after 8 months. Maybe just accept that you shouldn’t have sat on it for 8 months before installing it if you weren’t sure you were going to like it and were going to want a refund otherwise?
Well, since you’ve invited us to argue…
The Nameless One is not much different from The Master Chief or Geralt. The game is telling the story of a specific character. In this case, that character is a man. The fact that it’s based on D&D is kind of irrelevant; it sounds like you made an assumption that wasn’t stated anywhere, and are now trying to finagle a refund far outside of the refund window as a result.
While I certainly understand and sympathize with not wanting to play a character that doesn’t match your gender, it strikes me as kind of hypocritical to be okay with doing so for some games but not others. Personally I’d say, don’t play it if you feel strongly about it, but it’s not grounds for a refund.