The "button vs anchor" point is so easy to miss. Everything works when you click, so you never think to check. I run a React + Vite SPA on Netlify, and the "open the route directly in a fresh tab" check is a good one. A 200 that's secretly the homepage looks fine in every in-app test. I'd add one thing to the audit: check that each route serves its own title and meta tags, not just its own content. Did you find AI crawlers behaving differently from Googlebot on links that only exist after rendering?