Sometimes you don’t need a CMS and want to keep things as simple as possible. For my use case I wanted sailing club race officers to be able to upload Sailwave race results and display them in the most simple way possible.
To achieve that and ensure isolation from the website’s WordPress CMS I added a subdomain and configured a pretty Apache directory listing. Users now just upload files via FTP.
Assuming your website is running on the Apache web server, you can achieve the same with .htaccess and few tweaks.
See above example here, see the code which you can easily alter to suit on github.
More about this the Apache docs: