Apple TV working through the Cloud but not connecting to my Music and Photo Library on my iMac?

For accessing libraries on your Mac from Apple TV, use Home Sharing and the Computers app.

Photo sharing needs its own configuration.

Music Home Sharing is for compatible non-DRM local media files only (i.e. not Apple Music/iTunes Match subscription content).

What is your version macOS? Configuration is different for macOS 10.15 or later vs. macOS 10.14 or earlier.

Read here how to configure and use Home Sharing: Use Home Sharing to share media from a computer to other devices - Apple Support

The Computers app will try to find libraries on computers on the local network that have a matching Apple ID account for Home Sharing.

Unless someone else chimes in with a different idea, I would suggest to contact an expert from the Apple Support staff for further assistance. Contact Apple for support and service (phone numbers) or start your support request online (chat/​email/​callback).