Regarding Leverkusen, I think the performance Xabi Alonso had in this team was really good and now Leverkusen is in first place in the Bundesliga table while didn't spend too much money like Bayern Munich did this season with Tuchel and there is still a two-point gap between them and Leverkusen.
Also, the next game for Leverkusen in the Bundesliga is not hard because Union Berlin didn't start the season well and they had a disappointing performance so far.
I see some pretty great clubs last season at the moment not being able to compete much. Including Union Berlin, Mainz, Cologne. I don't look at what problems happen to the team. But I was quite surprised by Stuttgart they were able to play well and are still at the top of the temporary class.
Bayern Munich and Leverkusen were quite stable teams last season, so I understand they have good quality players. Indeed, Bayern Munich relies on money to buy players, but it is natural in football. Those two teams also have a record of never losing in the Bundesliga at the moment. So, now the challenge is the stability of the game until the end, those who are able to manage will be the Bundesliga champions. At the moment I am championing Bayern Munich, Dortmund and Leverkusen not with Stuttgart.