Lazy loading
Lazy loading defers off-screen resources — images, iframes, scripts — until they are needed. The initial page lightens accordingly.
In practice
Native attributes suffice for images: the loading attribute on everything below the fold. The common mistake: deferring the hero image at the top of the page and delaying the very LCP you were trying to improve. The rule is simple — the first screen loads immediately, everything else waits its turn.