Any sites takes longer than 3 seconds to load is just waving goodbye to their traffic. When it comes to SEO and user experience.
*Optimize all pages and posts
*Optimize Database
*Optimize file delivery system
*Clean up code and remove unnecessary codes and files
*Gzip compress
*Magnification of HTML, CSS and JS files
*Setup of browser cache and files cookies expiration time
*Increase load time per GTmetrix, pingdom and google page speed insights
Optional addons:
*Image compression and optimization
*Setup of your desired plugin like WP Rocket
*CDN setup
If you have any specific questions, Feel free to contact me via inbox.