The Planck length isn't really the grand slam for simulation theory it sounds like, position isn't actually quantized because of a thing called rotational invariance - basically, quantum mechanical systems (and really classical systems too) behave the same way if you rotate them x degrees and try again. If you did some kind of particle experiment, rotated your apparatus 10°, then did it again, you'd expect to see repeatably different results due to grid jank/snapping if everything truly operated on a square grid, but things act the same. Things can move around in distances smaller than the Planck length.
The Planck length isn't really the grand slam for simulation theory it sounds like, position isn't actually quantized because of a thing called rotational invariance - basically, quantum mechanical systems (and really classical systems too) behave the same way if you rotate them x degrees and try again. If you did some kind of particle experiment, rotated your apparatus 10°, then did it again, you'd expect to see repeatably different results due to grid jank/snapping if everything truly operated on a square grid, but things act the same. Things can move around in distances smaller than the Planck length.