Instead of using the receiver, have you thought about using the stake holder at the rear of the bed? One on each side holding three rods.
I could have , but don’t care to scratch up my truck and it is pretty convenient to have the rods in front of you while sitting on the tailgate
I've got a bed extender and actually never thought about doing that!
Kind of opens up a whole world of possibilities such as clamping on a board to your bed extender with the rod holders attached to the board, making it removable so you can still use the bed extender for your kayak.
You can then use the kayak to run your baits out, come back to shore and relax!
Attach a cleaning board to the rod holder as an extension to use as a cutting board for bait or cleaning fish.
You can thank me later!