I had to test an Access Package use case with a least privilege role so I assigned the user Identity Governance administrator role.
To my surprise, this role does not allow adding SharePoint Sites as a resource.
After looking up the Entra ID role, I found out that the SharePoint administrator role is needed to add SharePoint Sites as a resource.
I added the SharePoint administrator role to the user.
Once I added the SharePoint administrator role, I was able to add the SharePoint sites
