Re: Extract Test Steps from test Plan using API

How about using REST API:

 

To stored as XML in the Microsoft.VSTS.TCM.Steps field of a Test Case work item

 

API Endpoint

GET https://dev.azure.com/{organization}/{project}/_apis/wit/workitems/{id}?api-version=7.1

•    In the response, check the fields object for: 

"Microsoft.VSTS.TCM.Steps": "<steps id=\"0\">...</steps>"

•    This XML contains all the test steps, including inputs and expected results.

Connecting to Power BI
Power BI doesn’t natively parse XML from REST API responses, so you may need to:
1.    Use Power Query to call the REST API
2.    Extract and parse the Microsoft.VSTS.TCM.Steps field
3.    Use custom logic to transform the XML into tabular format