Bending the latch or the pillar is a completely false fear. The latches are super strong, the area they are attached to is reinforced and besides they're the body pillars. Body-on-frame designs in the 60s may just have been a tin can attached to a frame but today due to safety testing and regulations they're built very similar to a unit-body. The pillars are the important parts of the crash structure and so are like I said before: beastly strong. You'd have a hard time doing significant damage with a sledge-hammer.
So when I saw this thread the other day I went ahead and ordered a cheapie. Here is my review:
This is the unit I bought:
https://www.amazon.com/gp/product/B07CQWKK7X
The two aluminum structures (hook and step) are quite thick and obviously easily beefy enough to support a person. The hinge is a steel pin - 1/8" or so. The hook is designed in such a way that there is absolutely no way for it to come unhooked when loaded.
Once hooked it is quite solid and steady. There's no wobble or flex at all and the step is plenty big. I go about 190lbs. Due to the design of the pillars it works a lot better on the front doors than the rear. On the rear doors it's quite high and sits at an angle. So it's a bit awkward and puts the roofline just above the knee.
The instructions read as follows:
"Ues (sic) this Doorstep you can put all your bulky items on car rooftop or rack without any struggle as to make full use of in-car space, and enjoy a wonderful journey with all necessary items along with you."
It also carries this reassuring Lifetime guarantee:
"We stand by the quality of our exercise bands, and if they don't work out for you for any reason then send it back to us for your full money back. We know you will love them."