Largest Contentful Paint (LCP)

Hello,

After reading an article about Google Search to add page experience to ranking signals, I run a test on Google Page Speed.

I have a LCP (Largest Contentful Paint) that takes 8 seconds to load.

My website is under Wordpress, with LiteSpeed Cache, CSS and JS optimisation, Image optimisation, etc. I think I can't do much more.

Trying to understand where this slowness came from, I disabled all plugins to check if it came from that but no, at best it saved me 1 second.

I deleted all my custom CSS, but It changed nothing.

I deactivated all my GP Elements and it saved around 1 second.

Basically deactivating everything I hardly drops to 6 seconds.

So I thought it should be the layout of the page itself.

I did a test on a sub-domain, with a new wordpress installation, I copied exactly the same elements of the page and I have a LCP that drops to 3.7 seconds.

Would you have a rational explanation for this ?

Thank you for your feedback,
Samuel