Website response is one of the key factors to rank your website higher. There are a few reasons can cause a lower website. One of the common factors most site audit tools mentioned is server response.
As long the server is not overpopulated I will doubt this is a good reason. this rule should be deprecated. The modern web server with HTTP/2 should not be considered.
In my opinion, A slow website caused by these reasons;
Database – if the database is slow, this can affect the output on the website. The webmaster should tweak the database configuration if he or she can speed up the process.
External fonts from Google, for example, can slow down your website.
CSS and JS slow down a website. Everyone likes fancy and colourful websites. As soon as they looked beautiful and impressive, you are paying for the price, it is slowness.
Other queries, like a map, images from an external source can slow down a website.
High pixel and a big image is a common factor for a slow website. The clear and sharp image is larger in size, it increases the loading time especially for the slower internet users.
WordPress is easy to use, many good plugins are free. The more plugins you have enabled, the website is lower.
Fail to use gzip or known as deflate, this module in Apache web server helps to reduce the size of the loading page.
‘Failed to leverage with the browser’s cache. Like images, you can add expire header to cache it on the visitor’s browser for a period of time.
There are ways to reduce website loading but the question is how much. It might not be significant to some. There are a few services you can consider; A free Cloudflare but I prefer Sucuri as I experienced slower loading on Free Cloudflare. A good image compression utility but not losing the quality. Use CDN, if you are serving globally. I will see the points of using CDN if your visitor is limited to your hosted area.
If you are using WordPress, you a good caching plugin like WP-Rocket, it is a premium plugin but I think it is worth investing. Feel free to write to me if you have questions or things to share.