Bayern is a very wealthy club with a very sound financial policy. Basically, they can keep any players they want. They also don't let players go easily. Lewandowsky did leave last season, but that must also have had to do with his age. They handled that reasonably well with Mane. And Sane has also come over for that from Manchester City. I don't know if they plan to get more players, but they already got de Ligt in the summer, which was also a good reinforcement. It doesn't matter who they play with, the B team is also so good that they easily become champions.