Mass Assign Permission Sets

https://help.salesforce.com/s/articleView?id=000384595&type=1

Dataloader tips:

Insert, not update.
Permission Set ID must be 18 digit. Webpage mentions 15. I got error that the PermissionSetId was incorrect type until I used 18 digits.
- 18 digits was only seen when export with Salesforce Inspector or Dataloader.

Errors:

duplicate assignment: if the user already has the permission set. This is desired behavior.