Germans are often looking to cast specific roles, so offer the arias from pieces you are likely to get, not the ones you will get down the road! You’re debuttng aren’t you? So sing for the roles they’ll actually give you. They’re not going to start you with Manrico, Brunhilde or Butterfly. Unless you have a successful history of performing these roles, they simply can’t depend on you to get through the rehearsal period and a run of ten or 15 performances. Theaters dislike having to engage a last minute replacement for a major role so they’re going to engage you first for important but non critical roles. By singing the arias for such debut roles you show them that you understand how German theaters work and can fit in. There will be plenty of time to prove that you can sing major roles, meanwhile gaining experience so those roles will be even more effective.
My first roles in Germany were Gabriele Adorno in Simone Boccanegra and MacDuff in MacBeth. Neither opera rises or falls on those roles.You get to show what you can do but you’re not on all night. You gain experience without killing yourself.