Apple 4K TV (128GB/Ethernet) software update

Updating to 16.5. Download and setup went smoothly with no interruptions or error messages. The front light indicator doing what it was supposed to do, flashing rapidly indicating update proceeding but then the screen went black with no image at all. Indicator light on box still blinking away. That was 2 hours ago and that is what it is still doing. How long should the update take? Would I be safe unplugging and plugging the box back in going on the assumption that it just failed to restart? Do not want to turn my Apple TV into a useless brick. Been working great till the update attempt.