When you use CCC all css and js are concatenated, so unused depend on page scan. This is the limit of optimisation with CCC 😞 And if you don't use CCC Google devtools says to many htt requests for all css and js. So one approach is to verify:
Remove really unused CSS/JS (a good theme developer should do it)
Verify or activate http serveur zip compression
Verify or set long cache delay for css,js,image,font
Use a CDN is possible
Check your hosting performance
Check database performance