>An interesting alternative I've been meaning to try out is inverting this flow. Instead of using an LLM at time of searching to find relevant pieces to the query, you flip it around: at time of ingesting you let an LLM note all of the possible questions that you can answer with a given text and store those in an index.
You may already know of this one, but consider giving Google LangExtract a look. A lot of companies are doing what you described in production, too!
This is just a variation of index time HyDE (Hypothetical Document Embedding). I used a similar strategy when building the index and search engine for findsight.ai