Well, yeah, compared to Sugar Ray Robinson or Marvin Hagler, true.
But compared to Rhonda Rousey, Holly Holmes striking, speed, footwork were World Class.
Rhonda had judo, but as you say Holly had an outstanding work rate. Weaponizing stamina and work rate is a major attribute, IMO.
Holly just didn't have the power, and she wouldn't sit down on her punches to generate the power, but her speed, reach, timing and technique were "on another level" compared to Rousey — who was bewildered and befuddled by the difference.
Rousey wasn't KO'd by Holly because of Holly's power, but because of Holly speed and timing — combined with Rousey's cluelessness. It was an over-matching of skilled and athleticism.
When Rousey lost to Nuñez, it was an over matching of these things, plus power.