@enginckc 

Hello, the speed varies due to the LTE signal, distance and obstacles. 

You can compare the speed you can get from the MR200 and your cellphone. And try to change some settings on the MR200 to improve the performance.

First,  you can adjust the wireless settings, including the wireless channel and channel width.

Second, you can create the network connection profile manually with APN info. https://www.tp-link.com/support/faq/1663/

And please ensure that the firmware is up to date. 

Good day.