Thanks for the providing the support case number as I've reviewed some of the details. I want to share with you Changing Team Members - Founders Hub Portal | Microsoft Learn; you can invite team members to gain access to your Founders Hub portal.
If you want team members to be able to create resources, you do that in the Azure portal. Refer to How to create or delete users in Microsoft Entra ID - Microsoft Entra | Microsoft Learn for a step-by-step guide; the difference being you will perform these steps under Entra Id in the Azure portal instead.
Make sure you sign into the portal under the same account used to retrieve the benefit. I know you stated you redeemed separate benefit, but the identity created from that won't be the administrator of the Azure subscription you redeemed.