Bayern Munich has recruited Olise from Crystal Palace and it seems that the arrival of Olise is projected to replace Sane who is indeed injured and will also be out of contract soon, Bayern Munich previously tried to keep Sane in the squad next season but the arrival of Olise seems to change the Munich plan, what you said is indeed very true about Sane, although he is a selfish player but he is one of the players who often gives a lot of difference and improvement to Bayern Munich attack when Sane is playing, Sane contribution to Munich is quite big and I think there will be many teams that are currently lining up to buy him if Munich sells him later, even if later Sane decides to stay in Munich but it seems that it will be very difficult for him to be able to get a place in the main squad because so far Olise performed quite consistently and also still has a good performance as a right winger.
The Bundesliga is gradually changing as seen. Bayern Munich are bothered for their form next season, after a disastrous form previous season, they were trophyless and next season would be different. The new boss, Vincent Kompany have made good addition when it comes to players who are elite and competitive for his formation. Michael Olise is a brilliant signing for the club, he has better stats to contribute for the club.
Apart from the fact that Bayer Munich didn't perform well last season, there's nothing wrong with the club after all they have been dominating the Bundesliga for quite some seasons before Bayern Leverkusen stopped them last season so it shouldn't look as if the team is not performing well but had it been they dropped to not making it to the champions league it would have been different but they made it to the Champions League next season so it's fine and they still have all it takes to come back to good form in the upcoming season because they still have a very good squad.
Vincent Kompany may not look too good to be able to manage the team to greater achievements but we don't need to draw conclusions now, maybe when the seasons starts we can compare his performance. Indeed Michael Olise is a good signing for Bayern Munich because he performed very well for crystal palace last season after he played 19 games and scored 10 goals so the midfielder will certainly make a promising career at Bayern Munich and for the fact that he's still very young as he is just 22 years of age so he has a lot to offer to the team.