The best and recommended way to connect to copyparty (either from windows, linux, or macos) is with WebDAV -- this will give you much higher performance. WebDAV is also a MUCH safer choice when connecting over the internet, since it is just https after all. Meanwhile, exposing SMB to the internet is generally a recipe for, well... nasty surprises :-)
There are also very copyparty-specific reasons to not use the SMB-server, and these are explained in the readme. That's also why the SMB-server is not possible to enable in any of the official copyparty distributions without manually obtaining the necessary dependencies for that (impacket).