Sometimes I think I’ve got a good idea of sans character then I remember deep down I consider him kinder then papyrus and I have to come to terms with the fact that I have also fandom-fied him and it hurts, anyway congratulations on staying true to his character your the strongest soldier out there
lol don't beat yourself up. i wouldn't use "kind" as a qualifier, but i do think papyrus can come across as much blunter than sans. he's loud and banging and over the top in a way that exaggerates his other attributes, and one of those is his social awkwardness. he's shameless! both when he's being positive and uplifting AND when he's being a bitch. sans is more... contained. less vocal. but that's something that applies to his character in general.
more than anything i think—as jaded and more pessimistic as sans has become with time and his reset knowledge—both him and papyrus start from the same core personality. papyrus' kindness is obviously important to his character, but people tend to play it up too much in my opinion. he's just as capable of disregarding people's suffering and unhappiness for his own interests (empress undyne ending, king mtt ending, remaining our friend in spite of our actions) as his brother. he's just... very loud about his positivity and caring for other people and DOES want what's best for everyone... when it's not particularly inconvenient to him. lol.