I use Wordpress and I add critical CSS in the head section generated with: https://www.sitelocity.com/critical-path-css-generator.
In addition, I have this code for loading all other rendering-blocking CSS with Async and Preload:
<link rel=preload href=https://www.examplesite123.com/wp-content/cache/minify/37929.css as=style>
<link rel=stylesheet href=https://www.examplesite123.com/wp-content/cache/minify/37929.css media=print onload="this.media='all'; this.onload=null;">
<noscript><link rel=stylesheet href=https://www.examplesite123.com/wp-content/cache/minify/37929.css></noscript>
I use PageSpeed Insights and can therefore see that this method increases dramatically the CLS (Cumulative Layout Shift).
Before using this method to load CSS, i had only the following code without Critical CSS.
<link rel=stylesheet href=https://www.examplesite123.com/wp-content/cache/minify/37929.css media=all>
In this case the CLS was perfect, but other parameters like "First Contentful Paint" and "Time to Interactive" were bad.
So nothing else has changed on the site.
How can I reduce the CLS?