What issues are the most critical to fix first?

Broken links and 404 errors are critical to fix first because they directly impact user experience and search engine crawlability. Users encountering 404s will leave your site, increasing bounce rates and signaling a poor experience to search engines. Search engine crawlers also get stuck on broken links, preventing them from indexing valuable content. Fixing these issues ensures a smoother user journey and efficient crawling, which are fundamental for SEO. While missing alt attributes and meta descriptions are important for accessibility, SEO, and click-through rates, they do not create immediate dead ends for users or crawlers in the same way broken links and 404s do.