Unable to add admin user to my tenant

Hey all,
I am trying to add my colleague to the tenant and give him admin privileges (I have admin access). However, I do not see an Add Member button in the Tenant Members tab, even though the documentation says there should be one. This issue has been brought up in the forum a few times and the solution always points to the Teams view as in this post. But when I go to the Team dashboard, I do not see any Members tab. I have attached a screenshot of the Team dashboard here, as well as the Tenant Members tab. I would really appreciate some assistance on this.
Screenshot 2024-07-09 120858