The folder path should be in the following format:
http(s)://<NAS Domain Name or IP Address>:<Port>/<Folder Path>
The default port of WebDAV server is 80.
Suggest to a test on a NAS first in the same network with Public folder.
In my test, test NAS IP is at 10.5.10.91 and WebDAV service is running with default port 80,
admin owns Public folder permission.
So I use http://10.5.10.91:80/Public
Click Finish.
The Windows Security window appears.
7. Enter your username and password.
Tip:
Select Remember my credentials to save your credentials for the next session.
Click OK.
The shared folder opens in a new File Explorer window.
Connecting to WebDAV shared folders on a QNAP NAS in Windows 1... https://www.qnap.com/it-it/how-to/knowledge-base/article/connecting-...