You ask yourself how to configure the Autoptimize WordPress plugin right, when using Avada as Theme? This step by step tutorial shows it!
This tutorial was tested with WordPress 5.2.3, Avada 6.0.3 and Autoptimize 2.5.1.
If you have a custom.js or custom.css file you can exclude them. I prefer also not to optimize for logged in users, except you use Woocommerce or if your users have to log in to use your site.
Leave „Load Media-Queries Files Asynchronously“ and „Load Stylesheets in Footer“ off.
After making changes to the configuration test your results with Google PageSpeed Insights.
Write it down in the comments and i give my best to reply and help.