I don't where you get your "mopped the floor with".

With Jin and Tachikawa not participating in rank battles, Kazama was, presumably, the no. 1 Attacker, or at least a contender, but she reached and surpassed his score in a very short length of time.

her "in just a few weeks/months" isn't special considering she has been an agent and training for far longer than any other agent.

Yuuma has been fighting for even longer, but his solo points haven't reached 10.000 yet. By contrast, in that relatively short time span Kirie has achieved such a score that, despite not being able to participate in rank battles since, the only Attackers who have been able to exceed it are Tachikawa and Kazama.