I don't want to give you the wrong advice as I am not an expert with User Based license....but read the EULA Legal | Tableau Software
I think you need the core based license and turn on guest access "For purposes of Core-Based Server License, Authorized Users do not need to be uniquely identified."
Is your corporate website based on wordpress? You can use a service account and restrict the view in the dashboard and embed it using the api. If you need help, you can contact me and we can see how to help you out in this.