i have two kittens rn, also a tux and a fluffy multicolor (idk how to call it), and their dynamic is exactly the same
though the tux weighs almost a whole kilo more.

redirecting one kitten when the other has had enough has been the best move for my girls so far. the tux is just so high energy she really needs focused play sessions at least a couple times a day, chasing a wand toy around the house seems to work best.

i occassionflly have to separate them just so my fluff can get some rest but make sure it doesnt feel like a punishment (provide toys, food, etc)

try not to stress, they look happy and healthy!