Custom module that can define and have settings referenced (Craft 3)
So based on a bit of research. I don't think you necessarily have to create a settings model, if the settings are purely required from a config file. You could use something like:

$settings = Craft::$app-&gt;config-&gt;getConfigFromFile('configfilename');
$exampleSettings = $settings['exampleSomething'];


$settings would be an array, which you could then access each array key.