Chronologically, swapping Kiwami 2 and 6 makes sense but from the enjoyment standpoint I'd keep your order as is. Kiwami 2 is a better game than 6 and the stories are mostly standalone, 6 reduces most of the classic characters to mere cameos.
Frankly, the same can be said about 0 and Kiwami but here playing in order makes a lot more sense as the stories are closely connected.