He'll be fine. He was never going to keep up his scoring rate and is still a great finisher, but difference is he's also just getting more and better chances now. Doesn't help that our systems have been quite weird and not one of our attackers have been very consistent, points to a systemic problem for me.
Either way I think Cavani being here will help him loads. Neither Rashford nor Martial are long term strikers. Greenwood has that movement and knack to get among the chances. He can learn from Cavani and then after these 2 seasons that Cavani is here, become that main striker with Martial on the left and Rashford on the right.