Bulk Gmail Recipient Reveal Tool

I have a Gmail account where many incoming messages show only my own address in the “To” field, yet I know the sender included additional recipients. I want a reliable way to uncover every hidden address those messages actually reached—across my whole mailbox, not just one or two samples—and export them for later use.

Here’s exactly what I need:
• A repeat-able solution that scans all selected emails in my Gmail inbox and programmatically pulls every address found in the full header (including any Bcc or undisclosed recipients Google preserves).
• Output as a clean, deduplicated list—CSV or plain text is fine.
• The process must work on Windows-based machines; I use Windows 10. If you prefer a small cloud utility or a local Python/PowerShell script, I’m open, as long as setup is straightforward and security best practices are followed.
• A short read-me or screen-share walkthrough so I can re-run the extraction on new batches whenever needed.

Accuracy of extraction and ease of use will be my main acceptance criteria. Looking forward to your approach and timeframe.