>>francz+(OP)
Copyparty is an absolutely incredible tour-de-force and has an absolutely insane feature set.
But if you want something rock solid that probably solves your actual problem, I'd recommend looking at rclone - specifically the 'rclone serve webdav' command.
>>dmd+V2j
I use rclone to give me command line access to Google Drive from Debian. What would be the use case for webdav via rclone? Usually a cloud service like this has a native way to perform file transfers from a browser.