WordPress on Ubuntu – “File not Found” for home.php – Trying to Redirect to Root Folder

I don’t know nginx well but you probably just want

location = /home.php {
  return 301 /;
}

I’d put this in both the _http.conf and _https.conf files after the location = /robots.txt { ... } block. You possibly want

location = /home.php {
  return 301 https://$server_name/;
}

in the _http.conf version to include a redirect to HTTPS too.