Hope you find this useful. The original version used heuristics, but frankly it was breaking on many more PDF that I'd want to admint.
This new AI-based version that uses a YOLO detector trained specifically on Doc Layout dataset seems to do a very very good job.
Converted to ONNX of course, and also CoreML for the iOS app. I haven't yet tried on Android. Does it work for you if you have an Android phone?
I notice some inconsistent behavior with the placement of footnotes sometimes occurring inline with the text. That's kind of a tough edge case.