I have the same problem…
The cookie and privacy section in the theme menu is coming up completely without the section for the button(s).
No link and “ok” on front end.

Thanks for all the suggestions.
I have successfully applied most of the recommendations. Have an average score of 90.
However, I havING A flash of unstyled content after using inline and defer CSS in Autoptimize.
A unstyled menu shows up before page loads completely. Sometimes, content occupies just a segment of the entire width before finally occupying the whole screen size.
Had to turn on the page preloader to hide this error.
So, my question is this;
What CSS file should I exclude to prevent this FOUC from popping up?
You can navigate to have a glimpse of the problems.
Thanks..