Speed is the one page experience aspect Google confirms: "Core Web Vitals are used by our ranking systems." "Good" means LCP within 2.5 s, INP under 200 ms and CLS under 0.1, measured on real Chrome 1 users (the CrUX 3,948 data behind Search Console 1 's Core Web Vitals report); Core Web Vitals shows how to measure and fix each.
Keep expectations realistic. Google "always seeks to show the most relevant content, even if the page experience is sub-par", and good scores don't "guarantee that your pages will rank at the top". Aim for "good" for your users, not a perfect Lighthouse 30,824 score for SEO.