"Delayed Write Failed" when saving to a mapped WebDAV folder in Windows 10

Question

Problem

When saving to an existing file in the shared folder, the following error prompt is displayed every time.

Delayed Write Failed

Windows was unable to save all the data for the file \<server-url>\DavWWWRoot\hello_world.txt. The data has been lost. This error may be caused by a failure of your computer hardware or network connection. Please try to save this file elsewhere

The error indicates that a network fault may be the cause, but I can create, read, and delete files fine.

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Goal

A WAN accessible mapped network drive in Windows 10

WebDAV seems to fulfill this goal, but I am open to alternatives.

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Current Status

• Server with Kubuntu 19.x, running Apache's dav_fs module to serve the filesystem.
• Client machine running Windows 10.
• The shared file system is visible in WebDAV clients, and was able to be mapped as a drive in the client.
• Create, Read, and Delete are functional. Update is not.
• Both client and server are personal computers which I have full access to.
• Both computers are currently on a (wired) LAN connection

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Additional Info

• When connecting to the share via a client like BitKinex, I was also not able to overwrite the contents of a file, but no error was given.
• Windows still shows the updated content when I close and re-open the text document in notepad
• The shared folder on the server is at /var/www/share. It is owned by the www-data group that Apache runs under. I'm not well versed with file and folder permissions though, so I might have made a mistake
  • The output of ls -l /var/www/... for the share folder and it's contents is
  • /var/www/share/: drwxrwsr-x+ 3 www-data www-data 4096 Sep 5 08:22 share
  • /var/www/share/hello-world.txt: -rw-rw-r--+ 1 www-data www-data 0 Sep 5 08:21 hello-world.txt

If you have any suggestions or alternatives (i.e. a method of mapping SFTP shares as a network drives), I'd like to hear them.