I have no knowledge of Yor, so I'll list what I think are Ken's advantages and then let SxF supporters reply.
First, as always, AP. Ken leads with a 4X advantage (with the possibility of using Damage Boost), upscaling from
0.1 ton while Yor scales to
0.025
Ken has a monstrous LS advantage, Class M vs Class 10 means he can restrain and crumple her with ease, push her away by a notable margin when she defends, and basically shove her around with throws and such whenever he manages to grab her.
And although Ken's fighting style isn't strictly focused on that, Ansatsuken has elements of judo and he himself uses a variety of throws. Also, he's still going to capitalize on it once he realizes that, because of simple logic.
Yor also seems to be somewhat fond of throws and submissions, at least from her P&A, but if she tries to do any of them, she'll fail badly, and they could even backfire on her.
Ken seems to be the most skilled of the two in pure martial arts, which doesn't mean combat in general, mind you, but it's still something.
Ken hasn't fought only in professional matches, he has had his fair shair of real battles, and isn't new to fighting assassins.
Ansatsuken is already an assassin art, and although him, Ryu and Gouken don't fight to kill, such knowledge is rooted in the very essence of the style itself.
He fought and defeated FANG, who's a master assassin and poison user who could have killed (or at the very very least incapacitated) him with just a graze of his nails.
He's also accostumed to fight/spar/train with the likes of Cammy, who uses extremely acrobatic military martial arts that were once based on assassination, and given the series Ken's in, and the amount of tournaments and adventures he went through, he might have stumbled upon some of the characters who are either assassins, use weapons or both, such as Geki, Vega, Eagle, Sodom, Birdie (who he has canonically fought), the Dolls etc...
Question, does Yor really use poison as standard equip? Her P&A only shows her talking about poisonous stuff she used in the past, but are they shown in the series, or they are simply mentioned as a relic of the past?
Range-wise, Ken's got somewhat of an advantage with his flashy, kick-based martial art that allows him to fight simply with his feet, and giving him an advantage against those who primarily use their arms. The hadokens also are the real deal here, they can be fired both from Ken's hands and feet, and have more than enough range, adding the fact that Ken has a lifetime of experience in using them. Yor doesn't have an answer to zoning.
Throwing her stilettos doesn't seem a good option for her, she'd just lose them, and the scans show a nobody dodging them, meaning Ken's should be able to dodge them as well, given his senses and experience against projectile users.
Ken's fire is also a thing, not only because fire, well, burns, but also because it can be trasmitted through the hadokens and Heat Rush imbues all of his contact techniques with flames.