ZyXEL LTE5398-M904 bad wifi range

Hi,

I installed the aforementioned router, all works ok besides the wifi range.

It's much much worse than the previous router despite having stronger antennas.

I suppose it might be wlan country setup related, I tried changing it through ssh but have no idea how.

It has ZySH shell and 'set wlan country enable' command is not recognized.

Please advise.