Hi,
The sheer amount of content is the reason why you get that excessive DOM size issue.
You can either:
Try putting texts in 1 paragraph block if possible. This will reduce the amount of <p>
elements on the page.
You can also try splitting the posts into 2 to not get this report from page tester sites but it may cause bad user experience.
While Lazy loading DOM Elements is possible(with JS libraries), this can cause problems like broken eventlisteners or page not displaying properly. As for what’s the best library to do this, I’m afraid we can’t recommend any as this is a pretty advance site customization that is out of our scope.
A wise man once said:
"Have you cleared your cache?"