The beauty of a static website is course its simplicity: you don't have to deal with SQL servers, rights-management yada yada.
The problem with resurrecting your old webhosting site is, of course, legacy.
In this particular case stupidity and legacy. I transferred the static generated Hugo page to my webspace and the designated /www directory, which was, supposedly, completely empty. The problem: the site wouldn't serve. Unless I specifically addressed the sites index.html.
Why? The folder wasn't empty. There was still a old .htaccess file lurking around. And this file specified the landing as “index.php”, which does not exist. I don't even recall what exactly I was experimenting with years ago, but likely some variant of Wordpress.