Losing Frimpong and Wirtz was a major part of Leverkusen with Xabi. Look at the stats of how they played. Frimpong starts a lot as a starter and it's the same with Wirtz. I think Ten Hag will have big expectations and pressure because Xabi has left behind good stats. Ten Hag now just needs to work and make Leverkusen better. The German league is also not as tough as the EPL I think Ten Hag has a great chance to succeed with Leverkusen. In addition to these two, there are 3 more players being sold including Tah, Gustavo Puerta, and Odilon Kossounou.
Indeed Leverkusen lost good talents this summer, they lost Frimpong, Tah, Wirtz which will have impact on the team’s performance, their performance might actually drop next season putting the new manager Erik Ten Hag under much pressure to stop this from happening. I think the big question now is will the infamous Erik Ten Hag be able to prevent this from happening?
Ten Hag's unsuccessful Manchester United career has raised questions about him. There are those who believe in him, but there are also those who doubt him. Right now, Bayer Leverkusen will start a very difficult Bundesliga journey because they lost some of their star players as you said. Also, Bayern Munich continues to strengthen their team. The manager needs to prepare for this issue as soon as possible and make transfers. They need to have a good period to prepare for the German league. Now, the expectation from Bayer Leverkusen is to be in the championship race. It is not enough for them to go to the Champions League like a few years ago.