Robert Lewandowski shouldn't be an important problem for Bayern Munich, because they've got high scores without relying on Robert Lewandowski, so with Mane they should be able to adapt to new players and try to work as a team well to be able to shoot on goal and score. goals, in fact the game of football is not dominated by only one person but requires excellent teamwork.
Robert Lewandowski is one of the best striker Bayern Munich have and letting him go really affected them. But I know that the bavarians are having a hard time winning games but the boss, Julian Nagelsmann still have some promising youngsters that will do well for the club in the future. Musiala is one of the tough player in the club and his form have improved massively and also his value in the market pumped overnight to €80m. The club will be in a better shape sooner that I know.
As long as Bayern still has a lot of young strikers so they can still be trained to be good like Robert Lewandowski, Julian Nagelsmann should consider not releasing a few more core players so that it won't make it difficult for Bayern Munich to get a win, because if you only care about money with how to sell gold players then they will find it difficult to get good players again.