The module does only Ethernet BUT via ethernet you can push anything you want.
This is the reason why I chose this media as well as being directly compatible with BR2.
You can push rs232 and rs485 through the raspberry PI via a USB to 232 converter.
The Bluart does just that https://bluerobotics.com/store/comm-control-power/tether-interface/bluart-r1-rp/
I am building the following ROV for a client which requires RS485 for the Sonar and altimeter as well as RS232 for the CP probe.
All my cameras are IP FHD and fit inside the 2inch housing.
I am planning on making a GigE camera before the end of the year. I am waiting for feedback from camera manufacturers.