Thank you for your post!
I have reviewed your post and I understand that you have an Azure account with the "Microsoft Azure Sponsorship" offer per the screenshot you have shared. However, you are seeing a 'Not-supported' tag when attempting to view the Cost Management overview tab for defining scopes. It turns out that the Microsoft Azure Sponsorship offer does not yet support Cost Management data and you will need to change offers to one of the listed offers in order to obtain access to Cost Management data. Please refer to the following document here for a list of the current supported and unsupported offer types that support Cost Management.
In addition, I am sharing a document here with instructions on how to switch from a pay-as-you-go subscription to one of the supported Microsoft Azure offers to enable Cost Management data.
Please let me know if you have any questions or concerns and I'll be happy to assist you further if needed.
Thanks!
Carlos V.