This thing is barely even sipping my GPU while demanding a single CPU core call it god. Why not multithread the particle simulation, or, best practice, run it on the GPU rather than the CPU? Is it a Godot limitation?

When I started the game, I didn’t know how to make compute shaders work in Godot. Now I do, but the simulation code is pretty complex and it would take some time to reimplement as compute shader (and I’m not 100% sure all the features of the simulation code would be possible yet). In future projects I will probably try setting up compute shader from the start.