Analogue Video to Network Device

I have Pi4/Emlid flight controller which connects telemetry and control over wifi network for Ardu Boat.
Currently I have 3 x analog cameras going through a 3 way switch with a 5.8Ghz video sender, then USB2.0 video receiver on the ground station.
Seems silly to have two separate systems when I could just stream my video feed over the wifi.

Does anyone know of a small device which can take a video signal and stream it over the wireless network? If there is no wireless version, I can put the router on the boat and connect on the ethernet.