The instructions for part 2 are missing info about how to handle the Four Of A Kind and a joker case.
Wasted quite some time because I assumed that the remaining joker would remain unused, but turns out it turns your deck into Five Of A Kind.
There are no suits in this game, so no limit of how many cards of a same kind can be in a hand. Five of a kind is explicitly mentioned in the rules of the game.
Oh oh, you're correct :(
How did I not notice that; guess too much thinking about standard card games, plus no hand in the example input is a Five Of A Kind.