Let's say your screen is blank, the remote does not respond, and you cannot reach the factory reset software menu at all. A hardware reset using the hardware button may be the only solution. Many Roku ...
If your devices only support up to 4K at 60Hz, a "premium high-speed" HDMI cable (18Gbps, HDMI 2.0) is perfectly fine. Again, just avoid really old or thin cables. Early HDMI cables (HDMI 1.4 or older ...