Ok, thanks for the answer.
On the GL-X750, the two antennas are for GSM, which makes perfect sense in order to maximize cellular network reception.

What about WiFi external antennas? The GL-X750 has only internal antennas, and the product i am searching for should have both GSM and WiFi external antennas to be a perfect fit for my scenario.

Any other product that I should look into in order to maxize WiFi coverage?

Thanks