If Sadio Mane will really leave Bayern Munich again after only 1 year, then i think this was definitely one of the most disappointing transfers of Bayern Munich in the last decade. Mane was an absolute world class player at Liverpool and when the first rumors started to appear last year that Mane might come to Bayern Munich i think many did not even believe it at the beginning. Then he really came and the expectations where extremely high obviously. Sadly it did not work out at all, at least not in the last part of the season. At the beginning everything was ok i would say.
If Bayern will sell Mane then they can save his very high salary of 22 Million € per year. This is even more important than the transfer fee they will get for him.
The big money for Mane can be easily paid by a club in Saudi Arabia, there are several clubs that are interested. When I read that Mane received 20 million euros per year, it was a big mistake. They should let him go for any price. I remember a team picture from the Oktoberfest where Mane was the only one of all the players not holding a glass of beer in his hand... over 35 people.