As a target for next season, Xabi Alonso will also try to get a treble winner, just because next season Bayer Leverkusen will have to fight in the Champions League. Of course Leverkusen fans themselves must have more logical hopes for Leverkusen's achievement in the Champions League because we all know that competition in the Champions League is always not easy to get through each phase until it reaches the final. However, on the one hand, I also agree with what you said that Xabi Alonso's own abilities still have to be the main appreciation at Leverkusen because he is definitely capable of taking Leverkusen to the semifinals of the Champions League next season.
In my opinion, this is a very difficult target for them to achieve, because in the Champoins League it will not be easy for them to get through smoothly. The team they will face in the Champions League will be much stronger than the team they faced this season, their most visible difference is in terms of mentality. The mentality of the teams in the Champions League will be much higher and that will be a challenge for Leverkusen.
But I wouldn't rule out the possibility that they could get it all. Before that, we also have to confirm whether they will be able to play well or not. Keep in mind that they played well this season and it is not certain that next season they will be able to do the same. So we have to first determine whether they will play well or not. Because everything is not visible at the moment because the league is still on holiday and there are no more matches, like pre-season for example. So we have to be a little more patient to wait for their game.