Your pipeline is fine! Cherche is not fancy, it just allow to create hybrid pipelines that rely both on language models and lexical matching which can help a lot. Also Cherche is primarly design for computing embeddings with Sentence Transformers which have a better ratio <precision / number of parameters>.

Here is a great paper from IBM following the retriever-reader paradigm. Love those "light" models that can be specialized by switching index.

IMO the loss of ChatGPT is still interesting for retriever-reader approachs to generate either human like or structured answers from input documents.

Here is a tool I made to create retriever-reader pipeline in a minute: Cherche, would recommend also Haystack on github !

It is called Slot filling, extractive QA may works :)