Downward force is the least strong orientation...there's just 2 bolts per side in that direction thru thin sheet metal that is not boxed on the last foot or so...even with the frame reinforcement inserts you can get...it still just braces it against pulling out to the rear, and not really against down forces.

Pushing the tow hitch upwards drives the hitch against its mounts, and up against the bottom of the rear bumper, bracing it more.

Hi-lifting from the hitch should be fine in a pinch...the left to right balance of the truck would be the bogey.