Sadio Mane struggles in the Bundelisga is not down to feeling comfortable or new environment; instead it has been down to niggling injuries; the Bayern medics have been unable to manage Sadio Mane fitness compared to his time at Liverpool; Going into his second season; i believe Sadio Mane fitness will be better and improve, he will already be accustomed to the training modules there and can get his fitness managed better. I am sure he prefers working with Tuchel than returning to the merseyside.
If it's still just a rumor, then just enjoy it first even though the certainty is still not necessarily true. It also doesn't matter to me if Sadio Mane can stay in Bundelisga in the Bayern Munich team, as long as it's for the better. But if after staying there, Sadio Mane's achievements have not improved and tend to be worse than before, then it means that it is time for Sadio Mane to find another team that wants to accommodate him and that is not in the Bundesliga.
Sadio Mane will return to Liverpool this is just a rumor I think. I don't think that would be true. However, if Sadio Mane returns to Liverpool, Liverpool's performance will become more stable. Liverpool will be stronger. But I think Sadio Mane will stay with Bayern Munich in the coming season. And if Sadio Mane fails to live up to the expectations of Bayern Munich bosses next season, he will have to find another club. I think many teams would be interested in signing a talented player like Sadio Mane.