Hi,
i am trying to add some files from my iCloud Drive to the Library, the only option i found is to copy the files to the device iPhone or iPad. I also added my oneDrive Account and could add folders as Favorites so that the files in there show up in the Library and i can stream them. Is this not possible with the iCloud Drive? Because the only option i found is to copy the files to the device then they show up in the Library.
Cheers
Timur
Welcome to the forum!
Infuse can’t use iCloud for video file storage (yet), only for settings and metadata. You can see what iCloud sync will handle here iCloud Sync – Firecore Support
You can also see what’s on the drawing board for upcoming releases of Infuse here Upcoming Features (updated 3/3/25)
You’ll notice that in the “Planned” section there’s “Additional cloud providers” so there’s hope that maybe iCloud could be one of them. 
Infuse might be able to add a directory of iCloud files to your library but unfortunately Apple does not provide an api for streaming so the files must be downloaded from iCloud first.