Remote Shutdown

I have several battery backed up 4g router units in my fleet. I’d like to be able to power them off remotely or schedule a power off time. This saves battery and cellular data. Is there some sort of MQTT command or remote shutdown available?
Battery backed up units have the ability to turn on when power is applied over usb. But I’d like to turn on the router at a specified time or shut it down at a specified time. I realize when the router is off, the cpu is not responding thus cron will not work. But if I can send an off command or set a schedule that would be fine

I do a remote or timed shutdown of my Hotspot with a Delock 11828. It can be controlled by WLAN and has an integrated timer.
It is only suitable for USB-powersupply.

But that doesn’t work with a router with an internal battery.

This is not available in our product.

When the router is turned off, the mcu has to take in charge of timming etc which is very difficult and complicated.
It is better not to turn off using software.

Revisiting this…
Is there an exposed pad on the GL-XE300 that I can short that functions as the power button does. The small momentary switch soldered onto the board is tricky to get to. Is that exposed anywhere else on the board?
I’m going to try to hook it up to a relay controlled by a normal ESP8266 device

Maybe you can make a remote control power relay using your ESP8266.

Yes, that is exactly what I was trying to do. I just was looking for the exposed pads on the circuit board to give ground/short out (simulate on/off button)