Step 9: Asynchronous CSS
Follow this documentation to learn how to use the Asynchronous CSS feature.
Access Nitro settings.
Enable Asynchronous CSS.
Enable the switch titled Enable Asynchronous CSS and then click the Save Changes button. Please know that enabling CSS async may cause issues for your Divi website. Disable this feature if issues arise or work out the problem file/s by pasting CSS file names using the Nitro Helper into the Exclude Custom CSS Queue - much like you did for Nitro