How did you handle with the Eliminate render-blocking resources in Magento 2 and Limit unused CSS it is about real treatments.
I have enabled Varnish, Minify CSS, JS, WebP, Image attributes added.
Following should be done :
For server end: -- Varnish -- make sure most of the pages are delivered from varnish Cache. For Front end: 2. CDN: for JS, CSS, and Media use of CDN will reduce hop time which in turn means faster pages.
Remove unwanted JS using requierJS and Require config JS.
Differ JS or Async objective load it as late as possible.
Advance Bundle JS
WebP and responsive images to reduce image payload. Check google PSI tool apply FCP and LCP filters and check.
Also go through this link :