I've been looking for an endpoint to get user information, specifically whether or not the currently logged in user is an admin. Is that information exposed by any endpoint? I haven't seen one.
Currently, there isn't an endpoint to track HubSpot user activity e.g. login information. That said, if your HubSpot account is in Professional or Enterprise and you're a Super Admin, you can view the user last active time. Learn more here: View users in your HubSpot account.