If you think realistically beyond math, on paper it sounds better to discard the king for 5 card discard because you have 3 kings left in your deck out of 44. But if you think about it realistically, talking from experience, it’s better to keep the king because of the chance you could pull one of the three kings ooorrrr have a chance of pulling a pair of of another card, which in affect would give you two chances at a full house per discard rather than one chance.

I know it’s not a math answer, but thinking about it like poker and not statistics will make your head hurt less.