Extremely weak LTE signal

Good day
We have build a small LTE base station using Openairinterface5G. For hardware, we are using a bladeRF x40, 2x omni directional antennas (7 dBi peak gain), and 2x 10m coax cables connecting between the antennas and the bladeRF.
When I sit inside the office, about a meter or a meter and a half, to 2 meters away from the antennas, my phone connects perfectly. When I take the small base station outside, I’ve got difficulties for my phone to connect.
When I am standing right next to the small base station which is outside, I get an RSRP reading of above -94.
We wish to know how to configure maybe the base station’s configuration file to get better signal output, and what additional stuff can we do to get better output from the base station when it is placed outside.
I am currently setting the Openairinterface5G rx_gain and tx_gain to both 150. I am also using band 3.
What is the max and min rx_gain and tx_gain the bladerf can handle? What is the max and min rx_gain and tx_gain Openairinterface5G can be pushed to? How will both impact the transmit power, I wish to have a better understanding around these fields as well.

Here is the configuration file for the bladeRF in Openairinterface5g:

This forum is for MyriadRF hardware and software projects, which neither BladeRF or OAI are, hence might be better to post in those communities.