For litter boxes for our cats, we’ve started modifying big Rubbermaid containers: just get a box cutter and cut out a section on the front (you cut out kind of a wide-ish U with a flat bottom) for your cat to walk through. You can decide how low to the ground you want this entrance to be (leaving it low for older cars who don’t want to hop or whatever).

I don’t remember why we started doing this, I think mobility concerns and a cat shitting on the floor. It won’t solve all problems, for sure, but it’s at least probably cheaper than some litter boxes (and the higher walls kinda keeps litter contained if your cats like to fling litter around as much as mine do).

I dunno, just wanted to throw it out there. Good luck with cats and everything else, friend