The tldr; is at the bottom, after the story mode writeup. Feel free to CTRL+END or hyper-scroll your way there, or read the machinations of my troubleshooting on your way there.
Sometimes when you finish large migration project you let your guard down, because you're riding that frustrating/tedious/complex project completion high. That's when another ask comes down from above. A deceptively simple one. Something like, "Hey, is Dropbox >$30,000 a year for us now? Can't we use Google Drive instead? It should be included in our account."
Gone. Gone are the feelings of success. Gone are the affirmations you gave to yourself. All have been replaced with a feeling of dread, one that rides on your instincts, because you can still FEEL the frustration from before, when you had no real backing from the stakeholders and the teams were arguing with each other about who's folders should be integrated where.
Cost cutting time came at Manufacturing Company 1 (AKA MC1). MC1 was trying to keep payroll the same, so they looked at nearly everything else. One of those else's was Dropbox. MC1 used Google Workspace, so Dropbox was 100% a redundant service, with an annual cost of ~$30,000. That's not an immense amount of money, but it is someone's annual take-home, or nearly so.
Truth be told, I liked this request. I didn't care for the expanded use of Dropbox for the exact reason MC1 decided to do away with it. In fact, I would much prefer using GW's policies to assign permissions based on department and group. Getting the data there wouldn't be too hard, I already have an idea on how to do it, but gracefully shutting users out of Dropbox would be frustrating to them. I would definitely have to go team by team as opposed to folder by folder, which meant that the folders had to all be synced first.
So, first step: repurpose the older Synology (the one that was severely under-provisioned), because I had already upgraded the 8 drives from 2TB to 8TB, so there was an ample amount of storage available for this project. With the understanding that the Synology Cloud Sync app could only sync a folder to 1 service, I planned on setting up a sync between the Synologys so that the current production file server was syncing with Dropbox, the older one was syncing with Google Drive, and they would sync to each other. This way I could start all the syncs and let them work wihle I created the groups, policies and everything elses needed before I started deprecating Dropbox accounts.
It took a couple of weeks to get all the TBs synced up to Google Drive, partially because I was hitting API limits and had to make some adjustments to the service account that I created, and partially because I was stewarding a crap-ton of data (~30TB at this point). But while that was working I was setting up and testing groups and policies in Google Workspace in an effort to set drive access set by department instead of directly managing read and write groups for each team in each drive. I had some success there, but had to rethink my strategy a bit due to blurred lines between some departments and teams. It seems that even though I'd reorganized the data there were still instances where the organization didn't completely fit.
I started with the product developers this time, because they relied pretty heavily on the Dropbox folders. I'd given them a heads up at the beginning and they'd started including links to the files in both Dropbox and Google Drive in the management software. And...it worked!
Mostly.
One...small thing, it turns out that SOME of the product developers had been storing data in personal, non-team Dropbox folders that they then shared with others. Dropbox doesn't give admins the ability to see or manipulate those, so there were some gaps. They were easy enough to do by logging into their Dropbox account as them (something Dropbox does let admins do with a notification going to the users) and download/upload or set up a separate sync if there were a bunch of files and folders. But it was a gap in my process, so I adjusted my script to check for that possibility when I got to other teams.
Once completed I made all the PM accounts read-only to the Dropbox shares for 1 week, after which I created a new Dropbox account called something like "ProductManager@MC1.com" and gave it the same read-only permissions. I then deleted each and every one of those users' accounts and transferred the contents to the new shared PM account I made. This would make sure that none of the files that were shared would lose their links, as some data was shared with vendors and suppliers. Vendors and suppliers would be attritioned to the appropriate Google Drive shares over time when new data would be made available to them, but removing their ability to access the data right now would be problematic.
Marketing, Sales, Manufacturing, Graphics, Logistics, HR, Accounting, IT, etc. All were collapsed the same way until there were only a dozen shared accounts left. Once those were left for a few weeks I did another round of consolidation for teams under the same VP or director, further reducing the accounts to 5 in total.
Project success! All data was migrated to Google Drive, new policies and groups made managing access easier than Dropbox did for our firm, and we knocked ~$30,000 off our annual OpEx.
tldr; I needed to reduce our OpEx spend, so I utilized the other Synology to sync the data from Dropbox to Google Drive, then started collapsing Dropbox accounts until we were left with 5 in total.
Total cost: -$30,000, no "+" here, this was a cost saving measure I made which hopefully contributed to retaining some payroll.