Since all FTP clients on your system behave the same, and since your hosting provider said that the server is fine, most probably it is an issue with your own computer.
I completely shut down my anti-virus and firewall, and nothing changed.
That's a good action to take while investigating.
But also please check that your router (and your firewall when active) has port 21 and the passive (PASV) port ranges properly forwarded/allowed.
To do that, external port 21, used by the server (i.e. your hosting provider), should be forwarded to internal port 21 (the client, i.e. your computer), and the PASV port range (say 50000-50009 - those are server specific, and normally determined by the FTP server - check with your hosting provider) should also be forwarded in your router to your computer. If your router asks you to specify a protocol, select TCP.
See also https://superuser.com/questions/729876/connection-to-filezilla-ftp-server-works-but-directory-listing-fails
If the above doesn't help, please try to change your WinSCP connection method from Passive to Active. The port handling will be different. There is an explanation on how to do that somewhere on this forum/doc section.