>>15040228>They showed light with different frequency travel different speeds with no medium or in free space aka a vacuumThat's literally not even remotely what that experiment demonstrated or argued. Did you even bother to read the fucking abstract?
https://www.science.org/doi/10.1126/science.aaa3035The experiment shows that imposing spatial structure on a photon beam alters the group velocity of the light in a vacuum to less than c, which is hardly a unique result (the paper even points out that waveguides accomplish the same effect). The phase/group velocity still follows vp*vg = c^2
