Bayern Munich is getting crazy and they are really trying to hire Kane with any situation and condition, since Bayern Munich needs to pay too much money for Kane they are even trying to supply the money by selling the players they have in their team.
They can even sell Mane, Benjamin Pavard, Marcel Sabitzer, Bouna Sarr, and Alexander Nübel to earn money from selling these players to hire Harry Kane. I don't know if they really do that or not but seems Bayern Munich wants to Hire Kane at any price even if they sell some players for him.

Sell Sadio Mane and bring in Harry Kane is a controversial decision consider that the two names had shine in the Premier League.
I hope Bayern Munich can be more mature in his condition, there's no guarantee Harry Kane will perform as well as he did with Tottenham, in this case Sadio Mane can be their reference before decide to bring in Harry Kane, especially since the fee required will be much higher.
There is nothing controversial, because even if Mane becomes an option to exchange to get Kane I think it is valid. Or maybe, Bayern Munich sold Mane first to a club that plays in the Suadi Professional League and with the money obtained then Bayern Munich brought Kane, that is also valid if done. After all, their rivalry is limited to the match and does not extend to their regular lives. You can also see the example of Ramos and Messi who continue to play rough on the field, but in the end Ramos and Messi can play together at PSG last season. So yes, there is no problem whatsoever between Mane and Kane, they remain fine and there are no controversial decisions.