Maybe I was looking st this all wrong.
Someone correct me here if I'm still all wet, but a wd hitch doesn't appear to actually take pressure off the trailer tongue to hitch ball connection, but rather it's pulling down on the trailer tongue/hitch and leveraging it, at the hitch ball location to pick up the back of the truck. Effectively putting more downforce on the tongue to hitch ball connection.
If that's really what's going on, then yes it seems plausible to say put an oversize wd hitch cranked up to more than just the tongue weight of the trailer. Trailer is stil planted solidly on the ball.
Idk about other unintended consequences towing like this, but seems worth a shot.
Another question is how much bending force upward can you put on the truss extension? Would think the same as it's designed for in the opposite direction.