Embed Dashboard in own asp.net web application using Power BI Reporting Server (On Premise)

Hello,

i would like to embed a dashboard in my own web application using Power BI Reporting Server (On Premise).

1. As far as i can  see the only possibility for the Power BI Reporting Server ( On Premise) is to embed via an IFrame?
2. if w use the IFrame embedding, the users always have to login to Reportsever ? what kind of authentications can i use in this scenario? Every user which will display the embedded dashboard needs to have a user/license in the PBI ReportServer?
3. Can i also use the Power BI JavaScript API to embed the dashboard "on premise" without using Azure/cloud? Are there other methods to embed? for example with a .net report/dashboard viewer control?

Thanks