Bayer refuses teams to transfer their players, they try to preserve the team, and even buy young players, so they bought a defender from Barcelona from U-19. I think after they were able to keep Alonso, it became clear that all further actions would be aimed at preserving and strengthening the team. Let's see what happens, so far everything looks good. Guirassi could go to Dortmund, it's a good transfer, Dortmund's attack clearly doesn't look as good as it should.
Alonso, who stays at Leverkusen, of course, still has a big ambition to bring Leverkusen back to be able to repeat his previous glory, and of course it will not be easy to do when currently the rival team team is starting to actively move in recruiting new players, reportedly some Leverkusen players are starting to be targeted by other big teams, so it will most likely be very difficult for Leverkusen to refuse every offer that comes later, Jonathan Tah, Frimpong, Florian Wirtz are the targets of many clubs at the moment, so I'm pretty sure that if Leverkusen releases 1 or 2 of those players, of course it will make their team unstable next season.
Currently Leverkusen have brought in Alex Garcia from Girona which of course will make their midfield quite capable, while bringing in a defender who is still 19 years old can of course also be a long-term project for Leverkusen, but for next season of course he is not ready to compete in Leverkusen main line-up, Alonso looks like he will have a very tough job next season and I hope he can deal with it.