Last year, the NVIDIA Shield TV, a $200 device if you get the Pro version, received an update to Android TV that forced a new UI for the homescreen that injects ads from a variety of premium streaming services [1]. There is no easy way to disable it as far as I know other than installing a custom launcher such as FLauncher [2]. The cancers of modern day advertising cannot be understated.
Good to know! I was looking into getting one to replace my Chromecast. If I have to babysit a device's software I might as well just build the hardware myself, too! Even more pain in doing that, of course, but at least it's self inflicted.
[1]: https://www.guru3d.com/news-story/nvidia-shield-tv-update-an... [2]: https://play.google.com/store/apps/details?id=me.efesser.fla...