This is somewhat of an old thread but I want ti say that nothing actually outright says that Spartan 3s augments are inferior to the 2s, in fact they are stated to be a "quantum leap" above the 2s and nothing else really implies that 3s are inferior to 2s, only when 2s are wearing Mjolnir does the text state they are superior to 3s and that's simply because Mjolnir augments a users strength and reaction time by multiple times + superior metallurgy and shielding in comparison to SPU armor. Despite that, 3s in SPI armor during ghost of Onyx were matching Blue team members in ability in multiple instances and even outdoing them, such as when 3s moved faster than Kelly despite Kelly being the fastest Spartan 2.
Spartan 3s were said by Kurt to be the best ever and he personally trained them as well, they are way better than most give them credit for.
All of this is a bit irrelevant admittedly, simply because Noble 6 was a Category II Spartan 3, which were Spartan 3s who's innate potential were equivalent to that of the 2s, pulling them out of suicide missions for even better training and equipment and even acquiring Mjolnir Mark V (b) which isn't said to be inferior to the standard Mark V.
Noble 6 on his own was causing Insurrection military bases to "disappear" soloing them, which no Spartan 2 has ever done. In general, Noble 6 was out doing solo suicide missions that were entirely classified by the UNSC and was even a top ONI brass personal assassin, he was just that much better than his fellow Spartan peers at the time.
Noble 6 should be able to best Chief at this time.