Unlike single-source Apple TV slideshow apps, Imagozo connects NAS/SMB, OneDrive, and iCloud in one app. Photos auto-cluster into story chapters by date and place. Show any embedded metadata and freely position each element in your own custom layout, with cinematic Ken Burns transitions. No account, no tracking, no ads. Everything streams directly to your Apple TV.
My family and I had this problem, the Apple TV screensaver just kept showing the same small batch of cached photos over and over. We also wanted to see the metadata on our photos, like the date and location, and pick where that text shows up on screen. None of the apps we tried could do both, so I just built my own.
One thing that still bugs me is that Imagozo isn't a screensaver replacement. tvOS doesn't support that yet, so you have to open the app to start it. Hopefully that changes at some point.
But I think Story Mode makes up for it. Photos from the same time and place get grouped into chapters automatically, and each story opens with a quick overview card first.
Right now you can add iCloud shared albums, OneDrive, and your own NAS through SMB.