Yeah, i Think Povetkin would just rag doll him in the clinch. But Povetkin also seems to have better footwork than Stiverne. Even if he's not catching him early on, Wilder do have to move like hell in the ring to avoid Contact, and by doing so: ultimately burn out of gas, then i Think Povetkin will cath him - god night.
Stiverne isn't a front foot fighter. Povetkin is and will cut him down. Wilder won't simply be able to jab and move. He will have to knock Povetkin out before he gets knocked out himself.
I don't think Wilder's jab is powerfull enough to hurt Povetkin like Wlad's. Sasha can easily get inside against him if he doesn't run all the time. And when he's tired... BOOOM