It's ... impossible, frankly, to create a space where holidays do not exist. People will accidentally wear a pin or a T-shirt or a sweater or whatever, people will barge in unnoticing and carry those events in with them, conversations will accidentally drift in directions ... even without a global pandemic and our complete lack of funds, there's no way an actual, physical establishment could be made to guarantee holidays won't intrude.
We still like the idea, though. A fictional space, representing the idea that it's okay to set an impossible boundary and be able to spend a while not having to avoid or shut out a societal celebration you don't belong in.
Not sure if it'd be better realized as a story, an interactive fiction, a Bitsy game, or something else.