The LCP is very high. the first images seems to be lazy loading as per the google report. If I go to theme.liquid in the head, i don’t see any lazy setting.
To fix this, you need to make a small modification to your image-banner.liquid file, not theme.liquid.
All you need to do is, in the image-banner.liquid file, find the first line of code that says: “loading: ‘lazy’,” (without the double quotes) and either delete it or replace ‘lazy’ with ‘eager’ (be sure to keep the comma after ‘eager’). That’ll take care of the Lazy loading issue.