Related, I often work with markdown docs (usually created via CLI agents like Claude Code) and need to collaborate with others in google docs, which is extremely markdown-unfriendly[1], so I built small quality-of-life CLI tools to convert Gdocs -> md and vice versa, called gdoc2md and md2gdoc:
https://pchalasani.github.io/claude-code-tools/integrations/...
They handle embedded images in both directions. There are similar gsheet2csv and csv2gsheet tools in the same repo.
Similar to the posted tool, there is a first time set up involving creating an app, that is documented above.
[1] in the sense there are multiple annoying clicks/steps to get a markdown doc to look good in Gdocs. You'd know the pain if you've tried it.