I'm only familiar with Knockout from her run with the Secret Six. Damn...
My introduction to her was through the ‘90s Superboy comics. And yeah, she had some promising details to her character (being an apocalyptan and having broken off on her own, having been a stripper as her day job without buying into that misogynistic crap that tends to surround that occupation, being completely comfortable in her skin and unapologetic about just being herself), but then they brought in her creeping on Kon.
Initially it was played off as completely consensual on Kon’s part (nevermind how wrong the fact that she went after him was), but it was later shown that she had been manipulating and mind-controlling him all along. It was made painfully obvious when she actually manipulated him into helping her do something that under normal circumstances Kon would never have done (I can’t remember if it was a heist or something else, but I do remember that Kon ditched a friend of his to leave with Knock Out).
Even when he realized she was manipulating him Kon had a hard time breaking free of her mind control. It was made obvious that she made him ‘like’ her, that she used any physical contact they had (or invading his personal space) to manipulate him by mind-controlling him into ‘liking’ the contact, and that any time he started to get more clear-headed and question things that she’d use that control and physical contact as a way to distract him.
I will applaud DC that they made it a big thing when he did break free of her, but I honestly fee like they simultaneously hinted at and glossed over a lot of the awful things she did to Kon.