Importing 5002 users into SharePoint Online with a work email

Question

I need to create a test to prove that the 5000 list item limit can be exceeded. More specifically Users. I have en Excel spreadsheet that contains 5002 users. I don't need the trivial data to be included, just name and work email. With CSV files, the limit is 250 and I cannot add the work email to it. I have looked at some powershell scripts but with my lack of experience with it, I can't seem to get it right.

So to be clear the question is

(How)Can I import 5002 users with a custom work email address?

EDIT: Up till now I've tried:

Looking at a console app but UserProfiles in SPO are read only when accessing them via CSOM

Powershell scripts so far are all for SP2010 or SP2013 and don't work for online

Answer 1

The profiles are based on your Azure AD Users so you have to start there. The username has to be part of the registered domain. Like [email protected] if you are not using a custom domain, if you use a custom domain then use that.

Create a CSV file with the columns necessary (listed below in the loop). Create new users with MSOL PowerShell. After establishing a connection use:

$pathtofile = filepath to CSV file

import-csv $pathtofile | foreach { 
   New-Msoluser -userPrincipalName $_.UserPrincipalName -displayname $_.displayname -firstname $_.firstname -lastname $_.lastname -password $_.password 
}

Once you have the user accounts created the SPO User Profile Service will import them.