I haven't watched them much, but stats wise he doesn't look bad, in the league he has 7 starting appearances. Their record in these games:
5W-2D-0L, 18 goals scored, 2.57 goals pg, 2.43 points pg
Thats not bad, well above their average. Of course some of it is again fodder opposition as he is 2nd choice behind Zapata, so naturally Zapata has started some of the more challenging games. But if I'm Atalanta I wouldn't mind cashing in on Zapata now, as he's leaving in summer 2023 anyway, the ~25m or whatever they can get from Newcastle is a lot for them.