I'm glad that you were able to resolve your issue and thank you for posting your solution so that others experiencing the same thing can easily reference this! Since the Microsoft Q&A community has a policy that "[The question author cannot accept their own answer. They can only accept answers by others] (https://docs.microsoft.com/en-us/answers/support/accepted-answers#why-only-one-accepted-answer)**)", I'll repost your solution in case you'd like to "[Accept] (https://docs.microsoft.com/en-us/answers/support/accepted-answers#accepted-answer-in-a-question-thread)**)" the answer.
Issue: How do I fix Azure Trusted Service Account error while signing certificate
Solution: The issue was with your authentication "InteractiveBrowserCredential" was not working for some reason. You had to disable all authentication options except Azure CLI.
Please "Accept the answer" if the information helped you. This will help us and others in the community as well.