So an update. After 6 months, the power step and first step in the RV are spongy again. I decided to fix it for good this time.
The aluminum TMC used horizontally to support the step was, at best, 24ga aluminum angle. Slightly thicker than a beer can. Mine cracked like humpty dumpty.
So I went with steel. I made a U shaped frame out of 1/8" 1x1 angle iron. A few welds and drilled a few holes. The bottom of the step box is now supported by the side of the RV instead of the side of the step box. Its as solid as a rock, my 275 lbs body can stand on the power step and bounce and it doesn't move.
Here is the frame on the welding table.