But you're not able to set the two locations individually.
I'd want the appdata for Nextcloud stored in /mnt/user/system/appdata, which is where i store all my other containers appdata and is backed by cache. Then i'd want the data of files i upload to be stored in /mnt/user/nextcloud.
With everything in a single location it's difficult to do that, unless i set my nextcloud share to use the cache. It also means my nextcloud appdata files aren't backed up as they're in a different location.