I use GP on numerous sites, always upload small images (200kb or less) and use wp-smush and wp-rocket… whether I lazy load the images by having them fade in or use a placeholder or don’t lazy load I always get a low score for LCP. It feels like I make some changes and maybe the score gets better, but then I check again in a few months and its back to a bad score. Recently I have been seeing 5+ seconds and a red score for this.