The Wi-Fi on the TP-Link Deco X50-5G Wi-Fi 6 Mesh Router cannot be permanently deactivated. Here are some important points to note:

- The Deco X50-5G does not support complete deactivation of the WLAN. There is no option to switch off the Wi-Fi permanently, even after restarting the device.
- Some models have an ECO mode or Wi-Fi scheduling that allows the Wi-Fi to be switched off according to a schedule, but this is not a permanent solution.
- Deactivating the Wi-Fi via the system parameters in the web interface is only temporary and is reactivated after a restart.

If you only want to use the device as a 5G modem with a wired connection, the last option is to remove the antennas manually, but this is not recommended as it may affect the warranty and functionality of the device.