I'm not sure if Dante can only be harmed by spirit moves but Ken has a couple that can deal with Dante i think.
Assuming that none of the bajillions of "making your body explode into red mist" type moves for some unfathomable reason wont work on Dante. ken still has quite the arsenal
Meidatsu Hōkai Ken Specifically destroys undead monsters.
Kiyomi Shidan can erase Dantes mind.
Suieishin allows ken to duplicate any fighting style he has ever seen. kinda like taskmaster.
Muso Tensai allows Kenshiro to battle spirits.
Sōkin Jizai Ken Allows Ken to control another body with strikes. He makes someone shoot themselves in the head with it and he makes to other crush each-other in a giant bear hug of death using it. He could make dante beat himself up.