Managed retrieval for large amount of small docs

I have a very simple use case. A lot of small requests arrive each day, think forum messages. System should be able to search messages, maybe restricting search by metadata (title, message body, date intervals etc)

Here’s the problem: I don’t want to deal with all these vector databases, custom plugins, chunking, encoding, decoding etc. Looking for a fully managed service to do all that.

I don’t see anything on openai platform, except assistance api with limitation of 20 files which is a different type of rag completely.

Is there anything available on openai platform? Any recommendation for a managed service?