Performance / Core Web Vitals on each at scale?

Sales volume is not a storefront performance measurement. Test representative traffic patterns, merchandising, scripts, company accounts and integrations on the proposed build. Compare field LCP, INP and CLS where sufficient data exists, using lab diagnostics to investigate bottlenecks. Also test an order during a slow or failed backend integration. A high Lighthouse score on a stock theme does not prove the deployed store or establish a universal performance advantage.

Official references: Google Web Vitals guidance.