You may look for the file vendor/koolreport/amazing/assets/fontawesome/css/font-awesome.min.css and replace it with fontawesome 6.x. Any other files/folders inside "fontawesome" can be replaced with the new one. As long as you have the "css/font-awesome.min.css" for Amazing Theme to be included. If you find the name of css file is not comfortable, you may change the filename inside "koolreport/amazing/AmazingTheme.php"

Dashboard Framework allows you to load custom css and js, so you can use to load your fontawesome pro v6, let try this:

class App extends Application
{
    protected function onCreated()
    {
        $this->css(["a.css","b.css"])
                ->js(["a.js","b.js"]);
    }
}

Let us know if this can help to load fontawesome pro lib.