Android Question Casting To Smart TVs

I think that you are logged in with both your smart television and your PC at Google Home. So what you say to Google Home is: 'display Crosby, Stills, Nash, and Young's "Southern Man Live 1970" on my smart television'. Google home then instructs YouTube to start/continue streaming to the smart television. I suspect if you see the opportunity to set up a web session in your app to YouTube, you will achieve the same result.

Update: I forgot to mention that the browser must have a chrome client to enable casting.

The fact that you can cast YouTube and Netflix from your phone without a problem rules out network problems.
What happens when you log in to Google Home on your phone, do you see your Samsung TV in the overview of available devices?

I have tried many options to try this over the years that I eventually gave up. I now am using messaging to communicate with my Samsung tablet, from my app running on my phone, that can mirror to the Samsung TV. I also tried numerous devices to bypass this setup to place the TV vertically to mimic my app running in portrait mode. At this time it is not possible without spending hundreds of dollars with a new TV that allows this. I tried using different versions of Chromecast and I stupidly bought a Chromebit that can place a TV in portrait mode but doesn't allow an app to use it. So I have my main app on my phone send a messages to my tablet running a separate app that does the multi media stuff which entails displaying pictures and producing sounds over the TV's speakers. If anyone wants to purchase a Chromebit cheap let me know.

But to answer your question, no I haven't tried this. Not sure how to do this within my B4X program though.