Mane and Kane are both very similar types of strikers, so it's certainly not because Mane wasn't comfortable in the position and so couldn't be brought into the game properly.
However, you do hear rumors from the fanbase that point to your statement that Mane was/is not comfortable in the team. Mane also showed at his previous clubs, especially Salzburg, how perfectly he can score goals, so I hardly think that he has suddenly forgotten how to play soccer.
There was an internal conflict between Sadio Mane and Leroy Sane, resulting in a fight between the two and Leroy Sane was actually beaten by Sadio Mane at that time. There were unfavorable conditions when Sadio Mane moved to the Bundesliga where his productivity in scoring decreased and his instincts seemed to disappear over time. People associate this with his discomfort in the Bundesliga, resulting in a decline in Sadio Mane's form in the 2022-2023 season.
And rumors that I see Sadio Mane plans to leave Bayern Munich next season due to several considerations that he has to make a decision and if he stays at Bayern Munich it is not certain that he can contribute to the team and other reasons due to injury factors that made him less productive last season.