I was sad with lots of console warnings from embedded YouTube videos.

A cookie associated with a cross-site resource at http://youtube.com/ was set without the `SameSite` attribute.
A cookie associated with a cross-site resource at http://doubleclick.net/ was set without the `SameSite` attribute.
A cookie associated with a resource at http://doubleclick.net/ was set with `SameSite=None` but without `Secure`.

It also makes my already slow website even slower...

Then I found lite-youtube-embed from Chrome Dev Summit:

About 50ms faster and save 3.5MB resources.¹
Connects from www.youtube-nocookie.com².

I set up paulirish/lite-youtube-embed with doubleclick.net removed:

         // The botguard script is fetched off from google.com
         LiteYTEmbed.addPrefetch('preconnect', 'https://www.google.com');

-        // Not certain if these ad related domains are in the critical path. Could verify with domain-specific throttling.
-        LiteYTEmbed.addPrefetch('preconnect', 'https://googleads.g.doubleclick.net');
-        LiteYTEmbed.addPrefetch('preconnect', 'https://static.doubleclick.net');

         LiteYTEmbed.preconnected = true;
     }

Don’t forget to update your Content Security Policy (frame_src), so video from www.youtube-nocookie.com can be played, and img_src so preview images can be loaded.

Paul Irish also has a Pull Request that shows lite-youtube-embed would make loading YouTube embed 422X faster.

Thank you Paul Irish for making this gem!

There is another project called lite-vimeo-embed which does the same but for Vimeo embeds.