Azure Document Intelligence (especially with the layout model[0]) is really good. It has both JSON and MD output modes and does a pretty solid job identifying headers, sections, tables, etc.

What's interesting is that they have a self-deployable container model[1] that only phones home for billing so you can self-host the runtime and model.

[0] https://learn.microsoft.com/en-us/azure/ai-services/document...

[1] https://learn.microsoft.com/en-us/azure/ai-services/document...