Are you using CDN, and which one?
CDN is one of the ways how you can not only speed up your website but also provide more security and reliability. Many CDN systems offer additional functionalities which can provide many benefits to your website.
In essence, CDN systems should keep the copy of your website on several locations across the country, and to provide the same static content to a user that visits your website, from the nearest location available. The more the user is closer to the server, the website will perform better, and the content will be served much faster.
Our digital agency uses Cloudflare CDN for almost all projects as a default standard part of our services of developing websites and applications.