How to ensure the output of 4K@60Hz?

Please use HDMI to HDMI 2.0/2.1 Cable shorter than 15 feet in length and use as few cable adapters as possible. Then manually debug into desktop mode and set 4K@60Hz output. You also need to set it in-game if necessary.

Why do external devices such as mouse and keyboard not work well when docking?

Please use 65W or more or the charging adapter that comes standard with your Steam deck to ensure your Steam deck has sufficient power supply.

Why does the Ethernet not work?

After the SteamOS is upgraded, you need to manually enter the desktop mode and connect the wired network. Turn off Wi-Fi, or set the wired connection priority.

Why does the TV not recognize my sound barrier and deactivate the CEC device?

In the Steam settings, click Audio, there is output, and click "External Devices", and the audio can be transmitted to the TV.