there's been demos of using SQLite client-side, with the database hosted in S3, and HTTP range requests used to only fetch the necessary rows for the query.

there might be some piece I'm missing, but the first thing that comes to mind would be using that, possibly with the full-text search extension, to handle searching the metadata.

at that point you'd still be paying S3 egress costs, but I'd be very surprised if it wasn't at least an order of magnitude less expensive than Vercel.

and since it's just static file hosting, it could conceivably be moved to a VPS (or a pair of them) running nginx or Caddy or whatever, if the AWS egress was too pricey.