Side panel closed kind of changes everything.
Even the Dirtbox product you referenced, AFAIK, doesn’t work with the side panels locked closed, it just uses a hook/channel to “mount” with gravity.
You can see the company walkthrough of it here, starting at 10:10:
I personally think it would be hard (if impossible) to make a mounting connection to the interior of the camper that would hold any weight and not interfere with the opening or closing of the door panels.
(Though admittedly I won’t know the true tolerances of the panel gaps until next week when my camper is installed)
I recommend looking into the hardware/ build ideas around Maxtrax/ Recovery Board tables
I’ve only really seem them from Aussies, but this US based company seems to be offering a more off the shelf product option.
They even have a video very similar to when GFC deployment would look like:
You also may find success with something like a seasucker mounted table
or if you need something smaller, maybe even might cobble some stuff together from the Harbor Freight Magnet mounting gear holders
My goal is to find a way to place a diesel heater on the side, was thinking a flip down table some way. I have one of the tire tables but they are huge and take up space when transporting.
And if you want something similar to the step but a little larger Amazon has “tire tables” from $60 - $140. I’ve used one a few times (as a table) and they are okay.