Hi @MarcelPaschke,
Ok, cool. You got my vote 🙂
I did have a look at the Attendance dashboard page. I did a network trace in the developer toolbar and it does look like Microsoft already has an internal endpoint for this.
https://teams.microsoft.com/api/webinar/prod/beta/webinar/somerandomguids/report/premeeting
That endpoint gave this response. However, I wasn't able to authenticate with it via Power Automate 😁
{"WebinarId":"somerandomguids","ArtifactCreatedTimeUtc":null,"Attendees":[{"AttendeeRegistrationId":"somerandomguids","AttendeeObjectId":"4143237b-47a7-4a02-bffb-075161a04ea3","AttendeeStatus":"Canceled","RegistrationDateTimeUtc":"2021-09-17T09:57:35.7130879Z","QuestionAnswers":[{"Order":1,"DisplayName":"PredefinedQuestionFirstName","Name":"firstName","Value":"John"},{"Order":2,"DisplayName":"PredefinedQuestionLastName","Name":"lastName","Value":"Doe"},{"Order":3,"DisplayName":"PredefinedQuestionEmail","Name":"email","Value":"john.doe@contoso.com"}],"MeetingArtifact":null}]}
So, hopefully they will make something similar available to us in the near future 🙂