My TV has Android TV and cast built in. However, the built in cast is not the same as the dongle. It can't do all the same functions like turning on the TV.
I can ask Google Home or cast from my phone to YouTube or Netflix and it will turn on the TV and play the app. But, I can't just say to Home, "turn on the TV." I think the app is doing all the work. No app, no work. My guess anyway.