Try the concrete mixing tub (approx 2’x3’) at your local big box hardware store. It will hold enough litter it won’t tip over and it’s big enough they generally don’t get litter outside the box.
That's not my cat. Found it on tenor. Two of the 3 of mine are hulk sized beasts that have extra large boxes. They're the deep boxes that typically have those covers but didn't get that because many cats hate those. I have a hard as a rock copper eyed muscular 15 or 16 lb Bombay named Cole, a 10 or 11 lb Turkish Angora named Max and he's an epic lunatic like all Turkish cats and a literal gigantic giant Tonkinese/Snowshoe blend who is 20+ lbs and his skeleton is the biggest. Grumpy cat was a snowshoe mix with dwarfism seal pointed and "Big Boy" is a snowshoe mix with gigantism blue pointed. Had a Turkish Van in the past that lived to be 19. Max is about 14. Turkish cats are quirky sideshows. We never went for purebreds but the lady we have gotten them from just happened to have them and wasn't aware of breeds of them. I also have a ball python. Cats are obsessed with snakes.
Had a Norwegian Forest cat mix, long haired tuxedo, 13” at shoulder, 22lbs lean. Also a orange tabby that measured 34” nose to tail. Needed the BIG mixer tub! Thank God for the enclosed patio w/cat door.
