Global User Synchronization is not pulling in user

We created a user via 'Create User' (i.e., not the Security Console) successfully; username, email, person number, etc. We ran 'Synchronize Global Users' a few times, but this user isn't getting pulled in when I query Global Users. I have not ran into this before. Is there a timing consideration after creating the user? Other prerequisite jobs?

We also tried to use Advanced Access Requests right away, and the request is in stuck in 'Awaiting User Validation', but my thought is that's because the Global User doesn't yet exist…