I’m stuck at Campaign 9-8 Cape of Despair. How can I win this?

Hi My team level is now 58. My main heroes are Oya, Julius, Celeste, Astharos, and Fafnir Which are purple level.

I have other purple which are Phobos, Jhu, Elmir, Maya, Facelesss, mushy and shroom, Dante, Lars, Kai, Thea

In this chapter 9-8, there are Aurora, Dante, Luther, Peppy, Keira, Fox and they are really overpowering.

Any ideas how can I build up the team? Thank you.