The official Nextcloud iOS app allows you to access all your files on your Nextcloud, and more.
Features:
Read, rename, copy, move, delete all the files stored in your Nextcloud and send them to other App.
Display documents, photos, videos, audio files.
Automatically display previews of images and videos.
Create new folders.
Add any kind of data (documents, templates, photos, videos, voice memo, etc…).
Tag the most important files and folders as ‘favorites’ or ‘offline’ to consult them offline.
Use the Passcode function for an advanced level of protection of single folders or to prevent access to Nextcloud to other potential users of your iPhone.
You can enable the automatic loading from the camera so your photos shots will be available on your Nextcloud.
You can enable memory optimization Nextcloud to save space on your iPhone.