@SKate Thank you for reaching out to Microsoft Q&A. Based on my understanding, you want to acquire access token to call APIM Management endpoint and would like to do without involving Azure AD.
These APIs are protected resources, and this will require identity with authorized access to these resources in azure. When you use
az login CLI command, it in turn initiates
authorization code flow (or
device code flow) and authenticate your credentials in azure. Refer Sign in with Azure CLI for more info and as you mentioned it requires service principal in Azure AD for automated tools when using CLI.
Other than CLI, you can also use Rest API (or MSAL SDK) to acquire access token using authentication flows such as Client Credentials, Implicit, Authorization Code etc. Check out Scenarios and supported authentication flows and for your scenario, use Client Credentials flow but it involves App Registration in Azure AD. So, to answer your question, I don't think you can automate without using Azure AD. Tagging Azure AD experts also.
I was wondering if this is for developer portal, have you checked Delegate authentication? Please ignore if you are already familiar with that.
Feel free to add a comment if you have any other questions. We would be happy to assist you. Please 'Accept as answer' and ‘Upvote’ if it helped so that it can help others in the community.