EDIT:
So according to this thread, this is a Google related change and not Nvidia?
In which case, similar to the banner issue from a previous update, you can get a different launcher (see comments for FLauncher) to avoid it
https://www.reddit.com/r/ShieldAndroidTV/comments/181vh4t/ads_at_full_screen/
Sorry, you say casting doesn’t really work well. Does it work at all from Android? We use that pretty heavily in our home. I guess the TV does have the Chromecast built in, so we could still use it.
I’m not in the Apple ecosystem at all, so I don’t know if it is a viable choice. I guess I trust Apple not to put ads on everything, so it might be an option.
To my knowledge no but it wouldn’t surprise me if someone found a way to do it. It’s just that chromecast/Google TVs is a lot more friendly and open. You can cast iOS or android.