I guess the best Sadio Mane can do is to leave Bayern Munich if they hired another forward and especially Kane because in that case, Mane can't have too much chance to play in the next season and since they are trying hard and seeking another forward, Mane should start thinking about his next destination before they make him stay on the bench.
It is likely a bad move for Bayern Munich to sell him because of how much Sadio Mane cost back then many teams don't was to buy him at the same price as Bayern Munich bought him back then so it was a bit complicated for Bayern Munich so likely they will make Sadio Mane stay and fixed his performance for other teams to crave him again, I really think this is the only option Bayern Munich have right now and 2 bids now is the failed attempts for Harry Kane and Tottenham is really fitting over it, so in this 3rd bid if Tottenham Rejected it again there is no choice but Sadio Mane to stay for Bayern Munich for a while,
Munich last season was not so good at the start of the season. but they are getting better and maybe you are right, when their competitors lose their key players, next season will be very easy for Munich. maybe even Munich will only focus on the Champions League. Don't underestimate the team in the Bundesliga. but Munich is still too strong for their competitors. Dortmund must at least invest in their best players for 3-5 years to break the domination of Munich. and so far that's not what Dortmund thought.
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,