Almost certainly barking up the wrong tree here, but I have been set the task of creating a canvas app for use embedded in our website. I realise that canvas apps are by design for internal use, but there is some functionality within Power BI for incorporating apps into dashboards, and then publishing said dashboards for public viewing. I have experimented with this and keep running into the same sharing problems for powerapps, but I wondered if there was the 1/100 chance that, using Power BI or any other method, a Powerapp's production could be accessed publically.
