"By the way, it seems there is a wrong labeling of TX and RX pads on the silk screen, and I have confirmed it on the brd file 3DR-GPS-LEA6-JST-v11-RELEASE.brd.
If the reference used is the GPS, then the RX pad is in fact connected to the TX GPS pin.…"

"Default configuration when shipped says that only UBX protocol is output to UART1,
Go to CFG ->PRT and enable 0+1 - UBX+NMEA for protocol Out for UART1."