Adding shutter time to the camera does not fix jello, it masks it a bit.
Jello is a direct consequence of vibration being transmitted from the vehicle through a camera mount to the camera. The sensor is being physically moved while it's capturing the image.
You can adjust the shutter time value component of exposure in a couple ways. I am talking about any camera; they call it the "Tv" or "shutter speed", not video frame rate. You can directly control the shutter electronically. You can add a filter that cuts light, so the camera automatically compensates. They're pretty much equivalent in their effect on shutter time.
However, slowing the shutter time on a moving scene will just blur the motion. You might not see the jello as a wavy line anymore, you'll just lose optical resolution on details that align across the direction of the motion.
Real answer: fix the jello. Motor misalignment, motor imbalance, loose motor, propeller imbalance, loose propeller, loose gimbal connection, temperature or moisture differences in the gimbal mechanics, poor gimbal control, all can cause jello.
