This feels a lot like the growing Vercel + Planetscale solution. (or Netlify/Cloudflare/Amplify + Cockroach/Supabase/Aurora)

Vercel provides CDN caching for static assets, edge functions, and lambdas. Planetscale provides MySQL as an interface on top of an effectively infinite scale Vitess cluster.

My app is a stupid pipe from my db to my user that goes through a single lambda function on Vercel. Pretty hard to beat.