Hi!
To get ahead of the timezones here are som info to get ROV position in QGC.
ROV NMEA position needs to be sent to the ROV, 192.168.2.2 at UDP port 27000
https://discuss.bluerobotics.com/t/how-to-display-gps-on-ground-control/1442/8
After that QGC will get the position and display it.
Way to send position is usually using Python script that fetch postion from Waterlinked:
One BR script for that: companion/underwater-gps.py at master · bluerobotics/companion · GitHub