lol
these are my problems:
Eliminate render-blocking JavaScript and CSS in above-the-fold content
Leverage browser caching
Well, your first problem is JS and CSS, not PHP.
Browser caching also has nothing really to do with PHP. For this solution, try something along the lines of this in your htaccess:
<IfModule mod_expires>
ExpiresActive On
ExpiresByType image/jpg "access 1 year"
ExpiresByType image/jpeg "access 1 year"
ExpiresByType image/gif "access 1 year"
ExpiresByType image/png "access 1 year"
ExpiresByType text/css "access 1 month"
ExpiresByType application/pdf "access 1 month"
ExpiresByType text/x-javascript "access 1 month"
ExpiresByType application/x-shockwave-flash "access 1 month"
ExpiresByType image/x-icon "access 1 year"
ExpiresDefault "access 2 days"
</IfModule>
The veeeeery long and indepth read about browsing caching can be found here:
https://www.mnot.net/cache_docs/