Cannot access admin.microsoft.com – need Global Admin role assignment

It sounds like you're dealing with a tenant administration issue rather than a licensing problem.

Since you don't have access to the Microsoft 365 admin center and there are no known Global Administrator accounts available, the next step is typically the tenant admin recovery process. Microsoft Support will need to verify ownership of the Microsoft 365 tenant before they can assist with restoring Global Administrator access.

To help speed up the process, be prepared to provide details such as:

• Your Microsoft 365 subscription or billing information.
• The domain associated with your Microsoft 365 tenant.
• Proof of ownership (if requested).
• The email address of the account that should become the Global Administrator.

Once ownership has been verified, Microsoft can determine whether any Global Administrators already exist and guide you through the appropriate recovery procedure. I hope you're able to regain admin access soon so you can configure services like Copilot Studio.