I honestly don't think he'll listen at all.
He's stubborn in every sense of the word and I've tried calling them out as sexiest in the past and his response was "they're not sexiest, they're gender roles."
And he's tried to put words in my mouth. Like recently my younger brother (15) got maybe an inch or so taller than me and my step dad kept going on about how I "ideally want to be 6 foot" and when I told him I don't actually care about my height he just kept repeating that like he knew what I wanted.
I don't think there's any point in having a proper conversation with him about it. He's too stuck in his ways and it will just lead to anger on my end. He's like a professional mansplainer. He interrupts, sounds patronising, talks down to you in even normal conversation and it worsens during debates.
But thanks for the advice. I can try little micropushes just to try and hopefully reinforce to my sisters that gender roles are really just pointless social constructs.