I'm voting Deku.
Kazuma's win conditions are bondage and sleep, from what I've gathered. Bondage is terrible against Deku due to his mobility, especially because he has psuedo flight and has dealt with Danmaku far better than this attack. Heck, apparently his shockwaves might even just blow it off course. Sleep is viable, but it isn't in character for Kazuma to use sleep immediately or at a distance, if he even CAN use it at a distance. The AP gap is over 3x from Deku's shockwaves alone, so he isn't outbrawling or outlasting him. His stealth move doesn't help since Deku at this % has huge AoE and has dealt with characters he hasn't been able to see before, so he won't play games or underestimate Kazuma.
On the flip side, Deku's win condition is to just punch or kick Kazuma a few times directly since his actual AP is way higher than his shockwaves, and KO him quickly. He's smart enough to be very wary of Kazuma when he sees he has multiple abilities, and will be trying to force the fight to end quickly from the get go. In character, Deku will use an aoe attack, see what Kazuma does, then go for black whip into direct hits.
Also, why is steal being brought up? Steal only gets rid of Deku's equipment, not his power. He can still shoot Air Force without his gloves, and he's still cosmically stronger than his shockwaves with his kicks when he doesn't have his iron sole. Everything Deku's equipment does is secondary help to complement his main power. Stealing one of them would just make Deku want to catch and beat the heck out of Kazuma faster with black whip, which can't be stolen and doesn't have a counter.
Basically, Deku will use his aoe and black whip to beat Kazuma down long before Kazuma can get the chance to use sleep.