I have the same issue on my Chromecast with Google and my Sony Google TV so think it might affect all google TV devices

Can you perhaps add a shortcut to the restart menu of the stock settings?

Hello! I was able to reproduce this as well. Unfortunately, it seems like this UI is simply not navigable via dpad on the chromecast with google tv. I'm not sure if it affects all google tv devices, however, since manufacturers sometimes modify this menu.

Dispatch doesn't control this interface, it simply asks android to show it when you hit the power button. It looks like I'll have to hide this button entirely on the devices that don't support navigating on it.

Unfortunately as well, I can't create a custom power menu instead since only the OS is allowed to send power down / restart commands.