Have run into the same problem. AppleTV receiver through “computer” app can pick up both computers’, minimac &imac, Apple TV libraries. They are all connected by Cat6a ethernet however library on mini Mac only shows three of 30 movies. No problems with library content from iMac. Have called Apple 5 times talked with upper tier techs problem still exist. Reinstall operating system deleted movie files and re-download have changed chrome setting and added new contact Apple receiver still does not recognize downloaded contacts from mini Mac. Problem started with OS Ventura iMac could not support the Os update anymore????
AppleCare tech question hooking up devices that were meant to stream and did know libraries on co computers could be access by Apple TV receiver.
Ticket is still open and unresolved