Hello @Sandy
Nice to hear from you again.
I assume that they need your passport in order to check your identity. In this regard it's only logical that they ask you to submit a copy.
Maybe @BildungsberaterIn or @Arrivo-EMSA can tell you more about the procedure and in how far it is common to submit these documents (or if there is a way to avoid it if you're uncomfortable handing it in).
Best regards,
Thorgen