Start with crawl errors and indexation issues - if Google cannot find and index your pages, nothing else matters. Then address Core Web Vitals, as page experience is a ranking factor.
Strong answers cover: site crawlability (robots.txt, sitemaps), indexation issues, site speed and Core Web Vitals, mobile usability, structured data, canonical tags, redirect chains, duplicate content, and internal linking structure. Best candidates prioritise fixes by potential traffic impact and can explain how technical SEO supports content strategy.
Tests SEO depth beyond content. Many marketers know content SEO but lack technical knowledge. Candidates who can conduct a technical audit and prioritise fixes based on impact are significantly more valuable.