Hello Martin Almeida,
Thank you for posting your question in the Microsoft Q&A Community.
From my understanding, you are not able to delete your subscription due to some errors being flagged.
To be able to resolve this, elevate your access to be able to manage all the resources and subscriptions. Kindly click on properties blade in your Entra ID and under the Access management for Azure resources, set the toggle to Yes. Click on the link to get more information about how to elevate access
Once you have been able to do this, this should resolve the issues.
If you still have the License-based issue after doing this, kindly access the Microsoft admin by visiting admin.microsoft.com and sign in with your Global Admin account. Please note that you might need to create a work account in the tenant and assign a Global Admin role to this account. The reason for this is that the External account cannot access the Admin Portal.
Once you have been able to access, go to License blade under billing to see if there is any License. If you find any, you need to cancel this license to be able to proceed.
Follow this link https://learn.microsoft.com/en-us/entra/identity/users/directory-delete-howto to get more information on how to delete an Entra ID tenant
Let me know if further assistance is needed.
Babafemi