Best kicking technique male and female? LOL. She is good but definitely not better than Barboza, Adesanya or Rockhold when it comes to kicks.
Adesanya's kicks are very accurate & well timed, but technique wise they're not the best. If you look at his round kicks, he almost always needs to take a setup step with his base leg to initiate his kick, and he doesn't fully turn his hip over to get proper power and drive through on his kicks. That setup step on his kicks is why Anderson Silva could see most of his kicks coming and easily duck under most of them.
Rockhold gets the hip turnover for good power but he needs work on his timing & distance. He throws his kicks from too close a fair amount of the time and jams himself so he doesn't get full power on them. Also, his posture & balance during the kick needs work, his recovery from a kick often leaves him in a poor defensive position with his hands down and his chin hanging in the air.
Barboza does things right if you give him space to step into a kick, his distance & timing is good and he turns his hip over fully to drive his kicks through. the problem is he needs to be going forward, he doesn't kick as well if he's forced to kick straight from his stance, and once you start pushing him backwards his form goes to pieces.
Valentina is actually better than all of them. She has Adesanya's timing & placement, she gets her hips turned over for full power & drive on the kick, and she has the correct posture & balance during the kick & kick recovery to start defending strikes even before her kicking leg comes back down. She can kick going forwards, straight from her stance, or going backwards with the same form & effectiveness. Now, does she have the same speed and power of the men? Of course not, she's a 125lbs woman, but looking purely at technique she's about as good as it gets in MMA.