Learn how to use the LiteSpeed cache plugin to generate critical CSS for your WordPress website. As of now, you do not need a separate plugin or software to generate critical CSS for your WordPress website. At keithrainz.me/shop/, I use OpenLitespeed on Ubuntu on high-frequency server from Vultr, that is why I score 100/100 on page speed insights.
How to generate critical CSS for your WordPress site
To generate critical CSS, the Litespeed Cache plugin on the LiteSpeed server can do that for you easily. All you need to do is switch to a server running LiteSpeed and install the LiteSpeed Cache plugin and follow the instructions in the image below.