I don't see the issue either. The Petrified condition does what you seem to be after, so why complicate things further?
A petrified creature is transformed, along with any nonmagical object it is wearing or carrying, into a solid inanimate substance (usually stone). Its weight increases by a factor of ten, and it ceases aging.
If you want to treat a petrified creature as an object in some situation then nobody is stopping you. I'm sure there are plenty of situations where it makes sense to change the ruling, but that's sort of the game.
A petrified creature is transformed, along with any nonmagical object it is wearing or carrying, into a solid inanimate substance (usually stone). Its weight increases by a factor of ten, and it ceases aging.
If you want to treat a petrified creature as an object in some situation then nobody is stopping you. I'm sure there are plenty of situations where it makes sense to change the ruling, but that's sort of the game.