I also don't think that Leverkusen will go very far in this tournament. It is even doubtful whether they are caring about this tournament either. But actually, I think that they must care about it this season. Because they are performing very poorly in the Bundesliga. If I were in their place, I would thrive for even winning the Europa League title. Because by doing this, they can join the Champions League groups directly too. It doesn't seem like they will be able to end at one of the top 4 places in the Bundesliga for now.
Bundesliga in this season is very competitive and Leverkusen will have to protect their position until the end in order to get a place for Champions League. They will play and try to go as most farther as possible in Europa League because it can help them to get more income.
However, their priority will be Bundesliga and Champions League next season that will bring them good income. I know if they are Champions in Europa League, they can be given a direct ticket to Champions League. But it is risky to use all resources to fight and hope that they can win the cup at the end.
Focus on Bundesliga and top 4 are wiser target for Leverkusen. With their resources, I don't think they have too good chance to win Europa League even if they totally prioritize it.