Hi Micha,
I think your question might be missing a bit of context.
Perhaps answering these questions would get your question some more feedback.
What is your result vs. your expected result? For example, if you want to rename a file when it’s stored in GDrive, where do you get the name of the file? From the name it has as a GMail attachment?
Are you getting any errors?
You said you’ve tried everything, do you have screenshots or anything that can demonstrate the problems and what you’ve tried so far?