Ideally, both. However, if you’re just getting started or if your site needs serious, basic SEO help like implementing title tags or optimizing images, focus on SEO. Core Vitals won’t do much for you if your website doesn’t rank well to begin with. In that case, updating SEO should be your first order of business. However, if your site is already attracting organic traffic through Google, make sure you shift focus to Core Web Vitals.