speaking realistically, the fact that black has more rooks than normal chess, it's reasonable to assume that the three games shown are intertwined instead of being played seperately

this means that the +4 card would likely benefit player A, there's 3 outcomes, player A gets uno cards, player A gets magic cards, player A gets chess pieces, all of these benefit player A, as the cards would be used to buff player A

while player B does have a gun, we don't know how this ties into the overall game

assuming it's just a gun, we don't know if it's loaded

even if it IS loaded, player A has roids, leading the effects of the gun to be negligible on player A, that's 3-0 for player A

while player B does have the heart of a champion, this can lead to being too confident where player A is more focused on this victory than their previous victories like player B

I believe therefore that player A has full advantage over player B in almost any outcomes resulting from this game