This doesn't answer your question but my Gdrive is a mess and I'm only one person. Typically I download the the contents on an annual basis in zip files, extract them to a Month/Year named folder on a portable drive and start fresh with a clean Gdrive until the next time it gets out of hand.
I would think Downloading first then using parsing tools locally would make things much easier to organize than doing it through Googles front end.
After thinking a bit more about it, what you probably need to do is make a requirement for all internal emails to be CC'd to a central address then use that address to download and or synchronize itself to an offline drive where perma links can be issued.
if you want to chat then feel free to drop me a line: haroun@dala.ai - would love to exchange notes/thoughts.