Fine, so I bought licenses but apparently Microsoft deletes "some" of the data. All groups were still there, users and the device ids.. but not the devices themselves. I could see all devices associated to a user but couldn't recreate or restore them in device management. Thus, I had to re-enroll multiple devices. Will migrate off Intune in the future, since it's garbage but haven't found a good alternative for Android devices yet.
Organisations that didn’t have an off-boarding option (do nothing, pay the minimum, I’ll deal with it) selected should receive monthly reminders, then every 2 weeks (to multiple people), and one per week until a VERY alarming one the week before. And, of course, have all systems shut down and the data archived for a grace period.
I hope they sue Microsoft for what seems neglect.