Google Pagespeed Insights is just one of the many tools website owners have at their disposal to improve their sites, which has common recommendations for all types of websites.
Here's a good article that goes over page speed and about how score doesn't always reflect the actual speed of your website.
We have a great article as well that will help you to increase the score using cache plugins. Each cache plugin has its own options which are not enabled by default. By adjusting the settings you can get a higher score on Google Pagespeed Insights.
Note that some plugins can work better on one website and may not help on another one. It depends on the server configuration, the content that you are using and what other 3rd party plugins are installed on your website. The only way to find out which plugin is the best is to install them and check the score.
Using more than one cache plugin is also acceptable.
Example of the score on a free hosting with the Divi theme for desktop
Most popular plugins didn't help much on this particular website, the best score was achieved using this plugin with optimal optimization.
An important part of the loading speed is the content that you add to your pages, pay attention to the images that you upload to your website, their size will affect the loading speed.
This article will help to optimize your images before and after uploading to WordPress.