Bayern Munich has indeed experienced a decline this season, but in my opinion they don't deserve to be labeled as playing badly as you say. The reason is that now they are still ranked 2nd, and if we compare the points they got in the previous season, there is not a very significant difference. That means they can still be said to be on the same path as they were in the previous season.
I can't say Kane is a curse just because he joined Bayern Munich, then Bayern Mnuich couldn't become champions. We also cannot deny that Kane is the top scorer for Bayern Munich and also in the Bundesliga he is the top scorer in the Bundesliga. He made a huge contribution to Bayern Munich, and he did it in his first season. He managed to adapt very quickly and prove his quality. and I think there is no connection between Bayern Munich's failure and Kane. In my opinion, this is just a conspiracy theory, because if Kane is a curse then Tottenham should be champions this season, but that didn't happen.
Yes, I really agree with you that Bayern Munich performance was not that bad as people are complaining about it, but the reason why people say they really performed poorly this season is because Bayern Munich performance did not meet their expectations; they expected Bayern Munich to continue winning the Bundesliga. If Bayern Munich is that bad, I don't think they will make it to the semi-finals of the Champions League. The truth is, even in the in the season that Bayern Munich does win the Bundesliga, they do always lose some matches, and this season they also lose matches, so seeing Leverkusen win the game without losing any games means this team is in great form, and they really do it more than even we expected from Bayern Munich.
I think what makes people complain about Bayern Munich is because they compare it to Leverkusen. Because if we compare it with Leverkusen then they have very significant differences, because Leverkusen has been extraordinary this season. I can't blame those who compare Bayern Munich with Leverkusen, because they certainly have the right to do so. But I myself prefer to compare what they did this season with what they did last season. If anyone in the Bundesliga compares it with the team that won the title this season, they will say that all the teams played badly.
Apart from that, we have seen that Bayern Munich have defended the title for more than a decade, so if they can't defend it this season it will look strange. I actually predicted that they would be able to defend the title again, but Leverkusen managed to mess up the predictions I made at the start of the season. Because if Leverkusen didn't exist, then now Bayern Munich would still be at the top of the standings.