“better late than never”

if it already got force-deployed, start noting risks and finding the problem areas you can identify post-hoc, and speaking with people to raise alert level about it

probably a lot of people are going to be in the same position as you, and writing about the process you go through and whatever you find may end up useful to others

on a practical note (if you don’t know how to do this type of assessment) a couple of sittings with debug logging enabled on the various api implementations, using data access monitors (whether file or database), inspecting actual api calls made (possibly by making things go through logging proxies as needed), etc will all likely provide a lot of useful info, but it’ll depend on whether you can access those things in the first place

if you can’t do those, closely track publications of issues for all the platforms your employer may have used/rolled out, and act rapidly when shit inevitably happens - same as security response

Limit access on both sides (user and cloud) as far as you can, train your users if possible. Prepare for the fire, limit liability.