Ruthlessness and xx 23... tracer missiles do i get the hit or the cancel all dices take first?

You hit, and you must apply ruthlessness.

Ruthlessness and xx 23... tracer missiles do i get the hit or the cancel all dices take first?

Hitting has nothing to do with doing damage, and only measures whether any uncancelled boom and kaboom results remained after the Compare Results step. That is what triggers Ruthlessness. What happens to the dice and the ship being targetted afterwards is irrelevant

Your Tracer missile doesn't work unless you "hit" the target and that is the same thing that triggers Ruthlessness. It doesn't matter that the dice are all cancelled before advancing to the damage steps.