Yes, we all know how much weight those YouTube embeds can add to your webpage, making your site’s user experience awful.
What if there is a fix?
Yes, there is.
You can now use the native loading-lazy for <iframe>.
You can use lazy-loading to defer loading offscreen iframes until users scroll near them.
The loading attribute for <iframe> is available in all lastest Chromium browsers.
Example:
<iframe src="https://youtube.com"
loading="lazy"
width="800"
height="500"
</iframe>
To learn more about making your embeds efficient on your website, visit this Google best practices page.