Any cable is nothing but wire
Any signal that is not RF and radiate a broadcast signal can be sent over any wire
USB cables, Ethernet cable, phone line, HDMI cable, it is just wire
You just need the correct number of wires
Why do you think there are hdmi over Ethernet cable adapters
Of which a link has been posted with the suggesting to pull Ethernet cable in the RV
No difference using rgb cable
In fact rgb should have less loss and less possible interference, because each cable is a shielded wire larger guage than hdmi or Ethernet