Hi,
my experience when trying to backup my data encrypted to my nextcloud server running on my shared webspace (took me a couple of days..):
The realibility was poor; I encoutered several "MySQL has gone away"s when uploading huge directories.
Sharing huge directories lead to time outs. Not all files were shared.
The NC encrytion module stores the keys also on the data-directory. So if someone gets access to your files...
For every file and user who has access to it, a separate keyfile will be created.
As the number of files is limited in my case; that's not desired.
Time stamps are not preserved when uploading files on a webdav server.
Maybe it works on a dedicated server. But on a shared server I would not recommend that.