Some websites load very quickly, despite having a large page size and many requests. These are the ones that go beyond the obvious compressing images and not putting too many ads on their sites. They make it a point to ensure their site loads quickly with every tactic at their disposal.
One way to make your site load quickly is to put the script src="script.js"/script tag (with brackets) at the bottom of your web page, just before the tag that closes the body. This should give you a huge improvement in load time. Using defer or async will not work with every browser,
Your goal should be to have your site fully load quickly for Google. The search engine favors sites that load quickly. You also want to give visitors a good experience, so you want content above the fold to load right away. Why should visitors have to wait for things in your footer to load before seeing content above the fold? If your visitors perceive the page is fully loaded quickly, they will be happy.
You can also speed up your site's load time by leveraging browser caching. This allows repeat visitors to load chached versions of your page very quickly as your server only has to return content which changed. You can set unique caching times for different files, such as your images.
You can also use CSS Minifier, a free online tool, to compress your CSS files. It will eliminate things like black spaces to make your site download faster. You can also use an online Javascript minifier or compressor/
If you have a WordPress website, evaluate every plugin on your site. You should only have ones that are worth the functionality they provide visitors for a reduced load time. Also, check for outdated plugins that significantly reduce your load time. For more information click here https://www.reddit.com/r/SEO/comments/h7f9ta/howcanawpwebsiteloadinunderasecondeven/.