For years (I even pitched it to Dennis Gustafson, the creator of Teardown) I've wanted to do a 3D falling sand game that could naively be described as Noita x Teardown, but outside of the technical challenges I haven't thought of a concept that truly takes advantage of falling sand automata and isn't just a sandbox.
The only thing I can really think of are games centered around construction and civil engineering, fluid dynamics, mining and infrastructure systems. I'm not sure if you have played the game "Infra" but it made me think it would be fun to have a procedurally generated structural inspection game based on real physics, and you were tasked with fixing it with the right materials and processes.
Another example would be a game centered around big engineering projects, like what you see on Discovery channel documentaries. Having to build or maintain a water treatment plant, or some kind of simplified oil rig.
Teardown did a great job of gamifying the mechanic of detailed destruction and physics but it did always feel like it was a story trying to sell the mechanic, which is fine, I absolutely loved the game.