Teach your kids things you enjoy teaching them and they enjoy doing with you. Raising kids is not an optimisation problem.

At a kid level, both chess and poker will basically be the same anyway. It’s about fighting frustration and taking the time to think about what you are doing and a lot of memorisation. It’s going to be probability tables for poker and a tone of tactic puzzles for chess.

At this point and to play the optimisation game too, if you want to give your kids a way to work on their memorisation and dedication, you would probably be better served by having them learn to play an instrument. It’s also a creative outlet and is socially useful.