Can you download a small zip properly?

Is it just large ones that fail or both?

What happens if in the Configuration ... Attribute Settings ... you turn the Redirect to OFF?

If this suddenly makes it work, then your hosting site is not allowing for the symbolic links to work that make the Downloads more secure ...

If that is the case, ask them why this .htacces file cannot work on your server that is located in the /pub directory
#prevent directory browsing -- for security
IndexIgnore */*

Options +FollowSymLinks -Indexes