Hi Benjamin,
Your first approach is the right one and you should investigate further why it isn't working. You can overwrite the import that Atlas is doing in custom-variables.scss, then place the resources in the /public/fonts/ folder in the themesource.
// Font Family Import (Used for google font plugin in theme creater)
$font-family-import: "fonts/googlefonts.css";
If you are having issues, can you please attach the error that you are receiving using this method?