Need help lowering LCP render delay

I need help lowering my LCP for my website homepage. When I was first attempting to fix this issue my total LCP score was 9,180 ms. I contacted Squarespace support via a live chat and they suggested that I  download the extension TinyIMG. I downloaded the extension and "applied" it to my LCP image, and my LCP score nearly doubled. (But) This time it was the render delay that contributed to my LCP the most. (It used to be load delay) and I haven't the slightest on how to lower that. I attached images below of the before and after of when I optimized the images using TinyIMG.

This image was before I optimized the LCP image using TinyIMG. Notice that the render delay was contributing only 25%.

This image is after I optimized the LCP image using TinyIMG. Notice that the render delay is now contributing 62%. Almost like it filled in the amount that load delay was contributing before.

Note: the LCP image I kept talking about is the "banner" image I have at the top of my homepage.  It's the one showing a compilation of recipe photos.

Thanks,

Julie