the issue seems to have been the cable; I'm now able to SSH into the robot using the cable. Hooray!
The commands you suggested to stop robothub-ctl also works, and now when I launch the launch file, it doesn't give errors about acquiring the camera devices. Hooray x2!
However, I'm still unable to view images from the robot on my own machine. that's because the robot's subnet (192.168.197.x) doesn't match my wifi network's (192.168.1.x). ROS2 doesn't support connections between robots on different subnets. I can think of two ways to fix this - 1) get RAE to connect to my wifi (without using robothub), which is something I want to do eventually anyway, 2) change the robot's IP address while connected over wifi so the subnet matches. Do you have advice on how to do either or both of these?