You need to rewrite and update the rules. It's getting a little chaotic :-) From what I wrote above and quoted from you, what you wrote yourself, it logically followed that the new rule applies only and exclusively to multiplayer! So logically, I had no reason to change it for 2 players. I consider multiplayer to be 3 or more players, which I logically assumed would only be implemented in the card version, not the digital version.
Regarding the composition of this particular case, the program is set up so that the last move on the black joker can lead directly to it or through it, so the value of the card doesn't matter if I go for the black joker.
Here, I modified the program so that in solo mode, the first move from the red joker is set to 1 step. You can try it out and test it. It makes sense to me in multiplayer mode because there are more people in the game and the last one in line would be at a disadvantage. With two players, it doesn't make sense to me at all.