When you raised the hitch, did you add a riser/drop extension?
A few years ago, I added the drop receiver and could not drive the MH due to the sway. The problem was the play where the tow bar and then the extension went into the MH receiver. There was a bit of play, side to side where the tow bar went into the MH receiver, but at the end of the towbar this amounted to about an inch of movement at the end of the towbar. When the extension was added, the side to side play multiplied to 3 to 4 inches.
The change to the CVR eliminated the need for the drop and improved the handling, but the cure was eliminating the 'side to side play' altogether.
Accomplished by using the hitch quiet or similar item
Hitch QuietBeverley and Ken