@竜吾 鈴木 Thank you for reaching out to us, As I understand you are looking for information related to Identity & Access Management between different service providers (Azure vs AWS vs Auth0 vs Firebase).
Refer to these articles for more information which might help you,
AWS to Azure services comparison - https://learn.microsoft.com/en-us/azure/architecture/aws-professional/services
Google Cloud to Azure services comparison - https://learn.microsoft.com/en-us/azure/architecture/gcp-professional/services
Azure and Microsoft 365 scenarios - https://learn.microsoft.com/en-us/azure/architecture/solutions/microsoft-365-scenarios
https://www.g2.com/compare/amazon-cognito-vs-microsoft-azure-active-directory-vs-auth0-vs-firebase
Let me know if you have any further questions, feel free to post back.
Please remember to "Accept Answer" if answer helped, so that others in the community facing similar issues can easily find the solution.