Temperature sensor on LTE routers

How can I get device temperature on LTE router models like GL-X750 and GL-X1200?

since these LTE devices might be placed in less environmentally controlled location for better LTE signal, it is quite handy to know the temperature

on X750 I can’t find /sys/devices/virtual/thermal/
Is GL-X1200 discontinued? It is no longer listed on GL.iNet Routers and Gateways Selection - GL.iNet

Yes. X1200 is EOL, but we still have some devices left for sale.