Is Google Pagespeed Insights complaining about render-blocking CSS? Are your first paint times sub-optimal because of that render-blocking CSS?
Above the fold CSS (as part of Autoptimize's "Inline & defer CSS") can help you improve, but most sites need different critical CSS for different types of pages/ posts and generating the correct above the fold CSS can be difficult!
That is where the "Autoptimize Critical CSS Power-Up" can help; you install it, add a criticalcss.com API key (paying subscription required) and the power-up will automatically create rules with criticalcss.com generated critical CSS. Moreover you can tweak rules, add manual rules, force inclusion of specific selectors, ...
