Cook has run with that form forever, its a non-factor, its already baked into her results.
She wins because she is an overaged SR (she should be a college freshman by age) who, to my understanding, has been coached by the same coach (her Dad) since before middle school, consistency and years and years of racing experience being the key.
Cook competeted in youth track including Junior olympics prior to HS while traveling the country scoring good results, finding key high profile fast meets for years, even through HS, and has built racing acumen. In Texas UIL HS XC, she has been very good and very consistent over the years finishing 5th as Freshman, 5th as a Sophmore, and 7th as a Junior in the UIL State 6A XC meet. In track similar consistent good solid results, she got two 6A UIL state medals in 2019 finishing 2nd in the 3200m and 3rd in the 1600m and last season, just 6 months ago, finished 4th in 3200m at the UIL 6A state meet.
She wins today because she obviously has lots of miles under her legs, lots of racing experience and has now flipped a switch and figured out how to turn quality runs that may have been close losses into big wins with totally dominating performances. Improving week to week this season, she finally won the Texas State UIL 6A XC meet in near record time but more impressively a massive near 1 minute margin of victory over the 2019 6A State champ she previously lost to. But then the really big performance improvements came. She ran the fastest time ever at the Kinney/Footlocker/Eastbay South Regional (considering the 2015 course change), significantly faster than runners like Jenny Simpson, Weini Kelati, and Jenna Hutchins ever ran at that same course. And she did that despite her crazy form, like I said the form is baked into the results. When you have so much experience, more than most all HS runners, and then make a big step jump in performance I think you have things figured out, you know how to race, how to take risks, when to make moves and punish opponents. The runninglane time agrees with this. Cook has the massive experience edge and wont be beat today.