I’m not sure it’s “various sources”, I think all the comment in various outlets is the same and comes from this
“BILD had exclusively revealed that Bayern sports director Max Eberl had already talked to de Zerbi. In the conversation, the basic interest of FC Bayern was deposited.”
I am pretty sure every single person in the world would take Kimmich's side over Tuchel. Tuchel seemed a bizarre choice at the time, he's just not the right personality for the job, and it has been proven so.