My testing with the PUT uploader and WebDAV setup uses nginx. I did at one point test with rclone on Android and that worked fine.
I recommend checking the requests being sent to make sure that the path being used is actually what you expect it to be. It has been a while since I looked at the code and I do not recall if the path is relative to the server root, or to the tiddlywiki file.
Personally what I have been using is an advanced version of the PUT uploader that also creates directories as needed, supports custom paths and nested directories etc. If I ever get the opportunity to clean that up and update it to use cascades, I will publish it.
Edit: the config UI for the PUT uploader suggest the path is relative to the TiddlyWiki file and not the server root.