So ...

When it comes to videos, there is a golden rule: don't upload videos to your own media library! They will kill your site speed! Instead, you'll have to use the embed feature to display videos hosted on third-party servers like YouTube, Vimeo, etc.

The problem? Even those embedded videos will require additional external scripts and files that needs to be loaded ...

The solution? The lazy loading technique replaces the embedded videos with a clickable preview image ... The video will be loaded and played only when your visitors click on the preview image ...

And yes, once again, we are going to use handy plugin ... A plugin called Lazy Load For Videos.

Here it is:

https://wordpress.org/plugins/lazy-load-for-videos/

It's a medium-size plugin (330 KB), so let's start with the usual speed tests ...

Here are my results before installing the plugin ...

... and the result after installing and activating the plugin:

Basically, the plugin doesn't exist ...

With that having said, let's see how it works ...