I will probably end up with a different solution
It sorts pictures by date taken
Has a better UI than NextCloud (personal opinion)
It is a lot faster in previewing images
Works with the Nextcloud desktop and Android client (or any other app that supports webdav)
Can organize photos in albums and collections (I am not really interested in this, but it's a nice to have)
I hope that it will officially come to Cloudron at some point.