Some hammocks, like
this one, come with side panels to protect the doors. They are supposed to hang from the grab handles or the clothes hooks. I was able to rig bungee cords to hold up the side panels. Mine wasn't the one from Duluth but it was a similar idea.
The hammocks didn't work out for me. My rambunctious dog was able to break through in a corner and scratch the vegan leather. I was using a hammock with side panels combined with the Tesla pet protector.
I tried lots of different things and here is what finally worked for me:
I keep the back seats folded down, giving my dog access to the entire back area of the car. The floor of the back is covered with Tesmanian floor mats. But those would get muddy instantly so I covered the mats with a 60 inch x 80 inch"cooling" dog blanket. I was able to bungee the blanket to the folded down head rests and use large binder clips to attach it to the mats in the back. I can still access the subtrunk because the mat and the blanket can fold up with the panel. Laundering the blanket is much easier than washing the mats.
For a long time I had a nice foam dog bed back there but my dog figured out how to use the dog bed to overturn his
unspillable water bowl. So he lost dog bed privileges in the car. BTW despite this failure mode, those bowls are terrific, especially for dogs who like to slobber water all over the floor. I use one in the house, one in the car, and I got a third for my dog trainer.
That dog is too clever for my own good.