Identifying all Shared Drive permissions of a user

Our company uses GSuite and has over 20 separate Shared Drives for various departments in the company. This causes an IT nightmare whenever we need to revoke access to someone such as a consultant who is outside the organization, as it is necessary to go into each of these 20+ drives and check if that person has permissions in that drive which needs to be removed. It’s also possible that they have additional permissions one specific files.

This has been mitigated somewhat by creating groups granting the group permissions, then it is only necessary to remove the person from the groups they are in. However, this doesn’t really help for people who have special permissions that cannot be generalized to more than one place; greating groups would only move the problem into have to search 20 or so groups to see if the user is a member of any of those groups. I tried going to the Groups page and simply searching for the e-mail address of a random person in one or more groups who happened to be outside the organization, and it says my search did not match anything when I typed the e-mail into the search bar on that page that says "Search for users, groups or settings".

So I’m looking for a more manageable way to identify everywhere in our Shared Drives that a user has been granted permissions, whether it’s on the Drive itself, or specific documents in the drive. How can I do this?