That's what the various string theory proponents start from. There's "too many" different subatomic particles, so there surely must be something smaller that they're composed of?
When we understand that everything that we see is a manifestation of a probability wave, then we will understand everything is a wave and end these foolish experiments.
And by difference, I mean, establish boundaries between objects.
the geometric structure of spacetime at planck scale is problematic, considering how you might visualise a planck polyhedron so that no space is defined in less than whole planck units i.e. all dimensions of length are whole numbers.
you have to do some topological trickery to make a discreet planck volume that works.
the thing about planck units is they are extrapolations that end at single planck length that has some problems just with basic geometry, as well as a supposed instability of a planck space spontaneously collapsing.
a planck unit volume must take a form that has dimensions of single planck units and pack together so that no smaller spacings are created. it cant be a sphere, at best it can be some sort of riemannian tetrahedron or triangle.
it would be conveinient if that level was a 2D plane, but it still has issues.