@Masih_Dindar 

Hi, the 300Mbps is maximum wireless link speed between the router and wireless client device, and the real wireless link speed will be affected by the wireless environment and also the client devices as well, could you please try different wireless devices to see if either of them could reach 300Mbps link speed?

Here is an instruction about how to find the link speed on wireless clients:

https://www.tp-link.com/en/support/faq/2265/

Please also try to change the WiFi channel from 11 to other channel to see if it would be better, also try to change the channel width to 40MHz.

In addition, do you mean the download speed is only 2MB/s when using speedtest? please note that 2MB/s means 16Mbps, so please double check it is MBps or Mbps.

And the download speed is mainly affected by LTE signal and the ISP, please check the network type, band and also signal strength on Advanced->Status page. If you have any wired computer, please connect to MR100 via ethernet cable to test the speed as well.