Ahhh… the search engine. Have you considered an inverted search index? It’s been my experience that the moment you place Airtable in between the user and the data, things slow down a lot.
This can certainly work, and latency wouldn’t be an issue if the external database were fast enough to return the results. In practice, this is a challenge and why I lean on an inverted index which can return results in milliseconds even on a very large data set.
Here’s a paper I wrote about this topic some time ago.