Conversation

"Encrypting your #Nextcloud files on the server"
[...]
Its main purpose is to encrypt files on remote storage services that are connected to your #Nextcloud server, such as Dropbox and Google Drive.
[...]
Because the keys are kept on your Nextcloud server, it is possible for your Nextcloud admin to snoop in your files, and if the server is compromised the intruder may get access to your files.

https://docs.nextcloud.com/server/16/user_manual/files/encrypting_files.html

you may want to add client-side #encryption

https://fediverse.blog/~/Contribu%C3%ADndoAoFediverso/gocryptfs