KARKAT VANTAS WOULD NOT BE THE TYPE TO READ YOUR BOOKTOK SLOP YOU IDIOTIC SHRIMP OF BASELESS ACCUSATION AND SHALLOW UNDERSTANDING!!!!!!!!!!!!!!!!!!!!
this is mostly headcanons/character analysis of karkat and i haven't read homestuck in like forever. this probably isn't accurate but i still have opinions.
yes, karkat would be the type to read romance novels, but he would be more choosy for which ones he fully commits to. i think romance serves multiple functions for karkat.
1) it gives him a chance to exercise his interest in interpersonal dynamics (cuz he's a blood player), to psychoanalyze the characters and imagine what about their relationship works or doesn't.
2) it gives him the fantasy of being truly wanted, and not only wanted, but being wanted for his real self. as a big fan of 2000s rom-coms, a lot of them actually revolved around the fake version you project onto the world, and your true self being loved, not just your persona. and yes frequently the "real self" was a girl that wears glasses or something really superficial, but i think karkat would project this onto his blood color. i think romance gives him a fantasy of escape from his tough shell of self-hatred.
3) it gives him the fantasy of having his shit together. rom-com leading men frequently fullfill the role of the one that seeks romance out, they're the ones that act first, and this would fullfill karkat's wish for leadership. a world where he stops fumbling bad bitches, isn't troll queer, and acts as a good leader.
karkat would imagine himself as both the leading man and the leading woman, capable AND loved for who he is.
romance is not just a horny fascination for him (though it's probably partially that as well), it is a coping mechanism, and i don't think he would settle for some of the romances that booktok reccomends. karkat is a massive bitch and would probably find complaints for most books booktok reccomends.
anyway, go watch 27 dresses and confessions of a shopaholic. both are amazing movies and i think karkat would like them because i like them and i'm just like him for real.