Great content on a broken foundation ranks nowhere.
Technical SEO is everything search engines check before they read your content. Speed and Core Web Vitals. Mobile-friendliness. HTTPS. Clean URL structure. Canonical tags to prevent duplicate content. A sitemap.xml so Google knows every page. Robots.txt to control crawler access. Schema markup to give context, not just text. Internal linking. No broken links or broken redirects. Technical SEO is the foundation. Content SEO is what builds on top. Get the foundation wrong and nothing else matters.