Storage App for Apple TV 4K

If you don’t want to use iCloud or a similar cloud storage solution, then you’ll have to look at local disks at your home. What kind of storage would you need (say - in the next couple of years?) https://www.wd.com/products/personal-cloud-storage.html

If you want to store lots of large files indefinitely online, you’ll pay a subscription fee to Apple, Dropbox, Google, or one of the others. ~1TB is about the same everywhere.

You would be using iCloud Photo library, which is supported via the Photos app on Apple TV. The point is that it is synced to all devices, including Apple TV. You can have it optimized so it isn't actually using much space on your phone, if that is the issue.

https://support.apple.com/en-ca/HT204264

What was the issue with iCloud?