Not sure where to share this, but microsoft has released its own markdown conversion tool
microsoft/markitdown: Python tool for converting files and office documents to Markdown.
It presently supports:
- PDF (.pdf)
- PowerPoint (.pptx)
- Word (.docx)
- Excel (.xlsx)
- Images (EXIF metadata, and OCR)
- Audio (EXIF metadata, and speech transcription)
- HTML (special handling of Wikipedia, etc.)
- Various other text-based formats (csv, json, xml, etc.)