How many GPS antennas do you have ?
Do you have only one which is connected to your AIS transceiver or do you have two, one connected to the AIS transceiver and a second connected to COM4 on your PC.
If you have only one, which is connected to your AIS transceiver, which in turn is connected to your PC using COM3, I would expect to see both AIS and GPS sentences in the NMEA 183 data stream. It seems as though you are using the VDO messages to provide your position to the chartplotting software. Quite valid, albeit unusual as most users tend to use NMEA 183 GPS sentences, although in this case it appears as though none are seen in your data dumps.
If you have a second GPS antenna that outputs NMEA 183 data and is connected to your PC using COM4, then no reason why you can't use that to provide position data to your chartplotting software. If that is the case I would suggest that your COM4 settings are incorrect as most NMEA 183 devices communicating over a serial
port generally use 4800 baud, 8 data bits, 1 stop bit and no parity. If you do indeed have a second GPS, you should double check the documentation
to ensure you are using the correct serial port settings.