Hey, I just wanted to say the curl option worked beautifully for what I was trying to do.
After the remote appliance runs a backup job, I wrote a script to run curl with find -exec after it backs up data to send the new files to Nextcloud, using a password protected share, and the remote system has no access to Nextcloud except for just the one shared folder. That did exactly what I needed it to do. 
find *.cfg -newer last-run-timestamp -exec curl -u $sharetoken:$sharepwd -T {} “https://my.domain.com/public.php/webdav/{}” \;