Rename your Apple TV -> Open HomeKit app -> Locate the Apple TV you want to rename -> tap to select it. On the bottom right hand corner of the screen find the “GEAR” icon to enter Edit mode. Good luck 🍀

Try unplugging the TV. I spend over four hours trying to get things to work in my set up. Read somewhere to reset the TV set by unplugging it. Did that and everything worked. Good luck 🍀