Wilder better starts to use jab and movement, because his chin won't hold up a round against any top-10 HW today. Once his opponent lands, it's over. Wilder has great power though so many his opponents would be careful in the early rds and won't land clean shots.
Wilder won't go anywhere near Povetkin. It will be like Povetkin vs Wawrzyk, and it ends within the first three rounds. I would say Povetkin KO1
I'd go with about 3 rounds. AP would have to be careful early as DW can crack, and has height/reach advantage over AP. And as others have noted AP isn't a fast starter. First good, clean punch AP lands and DW is in trouble.