From the loss of Robert Lewandowski to the team performance Bayern Munich started to dwindle their performance and it is likely shown at the start of the Bundesliga that Nagelsmann is always insisting for Sadio Mane be a top striker just like Lewandowski which is likely not happening because Sadio Mane wants his original position so Nagelsmann don't have any solution with that at the start of the season for Bundesliga but when he let Sadio Mane in his natural position Bayern Munich have performed well again, and even making incredible dominance wins,
Therefore, Sadio Mane does not need to leave the club, even if Bayern Munich succeeds in signing Harry Kane, because in my opinion, then a murderous bunch of Mane and Kane could be organized, like Mane and Salah in Liverpool. I hope Bayern Munich have enough patience to keep Mane and give him a second chance to show what he is capable of. Trying to make Mane the sole replacement for Lewandowski is, in my humble opinion, a mistake.
I think Bayern Munich still need Sadio Mane because he is a great player expecially when he is handling the position he can play better, their still needs of keeping Mane because he is a raw talent. Bayern Munich just need to sign a good striker who can always be productive in every game just like Lewandowski, sadio Mane can not play as a striker but if the club sign a good striker and with Mane it will be a good chemistry for Bayern Munich which will help them to win their games without any struggle.