> And there’s no serious way to understand the accuracy you get per use (on your specific unusual distribution of queries) without employing the expensive ML / stats engineers you probably thought you could avoid hiring by outsourcing to Algolia / Rekognition in the first place.

You may simply not be able to do this at all. You might not know how to tell good ML/Stats people from bad. You might not be able to pay them competitively.

You might simply want something that's better than nothing, with "nothing" being your realistic alternative. "Expert in-house ML team" is not an alternative many companies can get, and even for the ones that could, it'll take a while. What are you going to do in the meantime?