Do you like/understand Disbelief Papyrus?
I don’t like disbelief Papyrus. But the reason I don’t is because it just isn’t something Papyrus would do. I get it that everyone he knows and loves is dead, but despite all that, I don’t think he would hold a grudge. There is actually a fan fight I think is much better handled where Papyrus still meets you in the judgement hall, but even when he’s sending attacks at you he’s still trying to appeal to you and make you see that what you’re doing is wrong, and whenever an attack made a hit, he would flinch like he still doesn’t want to hurt you. And in the end he is so overcome with grief over losing his brother that he breaks down crying, and that’s when you either cut him down or spare him.