Mane is not happy about it and he shown his feelings many times. Even Salah made more key passes to Mane but it looks like it was too late to improve their relationship and eventually we see Liverpool failed to convince Mane to stay.
He want to move to another club at which he feels he will get better recogition. He chose Bayern but I don't know will he achieve it in Bayern. He might achieve it if Bayern sells Lewandowski and he will become their main striker. Then he will be a core of Bayern attacking system. If Lewandowski does not move, Mane will have to play at either left of right swing and his position will be like in Liverpool. Something is closely to a second most important player after Lewamdowski.
I think this strong reason why Mane leave Liverpool beside still have another problem with salary received by Mane small than Salah, I think bad impact for Liverpool after losing Sadio Mane have good chemistry with Salah. Need time for building new chemistry between Salah and several player have been arrived on Liverpool because team working is not progress instant and need time. But Jurgen Klopp have ready he loss favorite player like Sadio Mane and he know who will replace position on left winger side, I think Liverpool keep solid or not for next season we need waiting when league beginning.