I guess nobody is or should be worried about scoring Goals for Bayern Munich without that Lewandowski not playing anymore there.
He scored only so much Goals because the other players have been set it up for him most times , also there was a lot of penalty goals he has done.
Bayern Munich has so much very good players that can score goals , and i guess we will see a lot from Mane in the future.
I think depending with your opinion not have to worry about who will scoring goal for Bayern Munich after leaving by Robert Lewandowski as dramatically opinion. Right now Bayern Munich have loss central forward and Sadio Mane arrived to Bayern Munich is not central forward position, he play as left winger with Liverpool and looks he not ever play as central forward position put by Jurgen Klopp. Really need replacement for Bayern Munich who will be top scorer actually really need central forward, with substitutes player like Choupo-Moting still not have good talented can replace position leaving by Lewadowski and less chance for him will get regular position with Bayern on next season.