I thought structured output is a solved problem now. I've had consistent results with ollama structured outputs [1] by passing Zod schema with the request.
Works even with very small models. What are the challenges you're facing?
Structured output is solved, it is structuring data that's not, because that is an unbounded problem. There is no limit to how messy your data may be, and no limit to the accuracy and efficiency you may require.
I have used such models to structure human-generated data into sth a script can then read and process, getting important aspects in this data (eg what time the human reported doing X thing, how long, with whom etc) into like a csv file with columns eg timestamps and whatever variables I am interested in.
[1] https://ollama.com/blog/structured-outputs