In reviewing through your description, the key part is:
One site note is the Global Moderator also is configured with Full Access because that account needs to moderate and also serve as a Community admin.
Based on this, the current permissions of this user are something similar to:
as permissions assigned to a user are additive, the system sees this user as a "full access" account, so all full access accounts should receive the user registration moderation items.
As such, if you are wanting a single account to moderate user registrations, you should be able to assign only global moderation permissions:
This will then send the moderation items to their queue vs the full access admin queues.