Stabilizer jacks only have strength in one direction which is in line to how they are mounted. Those electric ones are usually mounted in a single track across the frame. This gives some support side to side but they will flex front to back. Only real way to stop that movement is to cross brace them in the perpendicular direction to the frame.
A set of
JT Strongarms will take care of your problem.
Best mod I ever did. Our long tt used to shake so bad that it broke the heads off the bolts holding the jacks to the frame. I added a set of Strongarms and it eliminated all movement, even with the kids running around.
