Technical SEO Review before we replace our Webflow site with Next.js

BACKGROUND We're a B2B fintech providing interest-rate data and analytics (swap rates, forward curves, government bond yields, FX, a blog and financial calculators) — around 280 indexed URLs. Organic search is our main lead-generation channel, so we can't afford to lose rankings. We've rebuilt the marketing site from Webflow to Next.js (App Router) on Vercel and are about to fully replace the Webflow site with the new one. We've already run our own old-vs-new parity check and fixed the issues we found, and we believe the new site is at parity — but before we flip the switch we want an experienced technical SEO to independently sanity-check it and tell us what to watch out for. WHAT WE NEED We want a sharp, expert opinion ahead of the cutover — not a months-long engagement. The main deliverable is an independent SEO review of the new site: your honest assessment of whether the migration is at parity with the old Webflow site and safe to launch, including a clear go / no-go read and anything that should be fixed first. Alongside that, please provide a "what to watch out for" list — a prioritized checklist of the risks that could cost us traffic: what to verify before we go live, and what to monitor in the weeks after. We'll leave the "how" to you — bring your own tools and process. We can share the staging URL, the live site, and our analytics / Search Console access once we start. A quick call to walk us through your findings is welcome. LOOKING FOR - Hands-on experience with site migrations / replatforming (ideally to Next.js / React / Vercel) - Solid understanding of how search engines crawl and render modern JavaScript sites - Comfort with Google Search Console and the usual technical-SEO toolkit - Bonus: B2B / fintech / data-heavy sites PLEASE ANSWER IN YOUR PROPOSAL 1. Briefly describe a site migration you've reviewed or led, and how you protected organic traffic. 2. When a site is rebuilt in Next.js, what are the first things you check before letting it go live? 3. What's your approach to making sure no ranking get lost in a replatform?