I honestly didn't know WevDAV was still a thing. It seems like a nightmare from which we should have woken up long ago. I do sympathize though. Every service implements (or implemented) it differently, or spottily, or partially. Is it another example of the adage that "even your bugs have users"?
Why is it a nightmare? I use WebDAV almost every day. All my online servers support it, and it makes it super easy for me to map them as a file system driver in Windows, allowing me to edit files directly on the server.