Chidori's technicalities' are slightly different from The FRS's, in my opinion..
The former possesses the power to harm even the likes of a Juubi Jinchuuriki Madara when streamed through a legendary, spiritual blade in The Long Sword Of The Sky.
While to achieve the exact same effect - the latter had to be amplified by several different elemental, and spiritual boosts in terms of the Modes - that the wielder ie., Naruto acclimatized to, throughout the course of this serialization.
So, although The FRS can likely penetrate, and drill through the sand - I wouldn't say that it has the quality that exudates a certain degree of "absoluteness" in it's nature - which likely disqualifies it from penetrating it without the boost.