What is the most appropriate way in order to use NextCloud for backup and syncing Apples Photos.app with macOS devices and iOS devices and for sharing pictures with frieds and relatives?
Install the Nextcloud app and let the Apple devices sync their photos to your Nextcloud server. Next, use the Nextcloud app to create share links which you send to your friends and relatives. This allows you to keep all of your data on your server and grand selective access to it. All persons you’ve shared your data with, are able to view it on any device they want using a web browser.
Install the Nextcloud app 
I recently tried this and now I can read my photos, but I can no longer make any changes.
I did make sure sharing was set and I verified permissions are set. So if this can be done I’d like to know the exact steps because I have tried this many times years ago with OwnCloud and they couldn’t explain how to make it work.
My last step was to share the library with my wife and now it is a read only file. During the transfer process to NextCloud it said it wasn’t copying symbolic links internal to the library so, I suspect all the hooks are no longer there.