https://www.transfermarkt.com/barcelona-submit-bid-for-lewandowski-ronaldo-lined-up-to-replace-him-at-bayern-munich-/view/news/406635There is fresh news about the possible Lewandowski transfer to Barcelona. It is said in the source that Barcelona have made their official offer for him and it is worth 40 million euros. The transfer fee is 35 million euros and there is a bonus worth 5 million euros too. I think that it is a quite favourable offer for Bayern Munich now. But they still seem decisive about not selling him until his contract expires next summer. This is making things really difficult for Lewandowski as he wants to leave now. If they block his way then this might reflect on his performance badly too.
€40m is quite good number for Lewandowski and Bayern should take that opportunity. First he is relatively older, they will keep him for 1 year then he will walk away free, it isn't profitable to keep a player who doesn't want to play in your team and as you mentioned this will affect his performance. Besides, Bayern has to find an alternative for him or find a new strategy with Mane arrival.