Look at @DFresh11 using high level soccer/football terms… In my experience the joker isn’t a position during the game… it is a position during SSGs in practices to simulate actual game scenarios. Most jokers have constraints… like they have to stay in a certain zone, have a minimal amount of touches, etc…
I’d assume Gelnovatch was using the joker as the connecter as you said above… probably a 2 or 3 touch connector that was responsible for an effective through ball that splits the weakened defensive shape.