some exceptions on Litespeed Hosters , Hostxnow (demi dedicated) is a fast web hosting as example.
My experience with Litespeed cache is (same with nginx settings) you will see speed the effect on your site after few hours- 24 hours, not within 5-10 minutes. Yes to reduce render blocking scripts, or combine css this result you will see after 5 minutes in gtmwetrix in waterfall, but speed needs some time to effect on your site.
Same when you using a cdn it needs few hours- 24 hours to work on your site.
But the down side is cache plugins left a lot of render blocking js and css Litespeed cache too, it is bloated with them.