well depending on how things pan out maybe she could get lucky
i mean, karkat would need to learn to respect her properly before he could be legitimately attracted to her
first and foremost karkat is attracted to a) people who don't take his bullshit and b) people he thinks can take care of themselves
he doesn't think nepeta can take care of herself
so he doesn't really see her as a potential romantic partner, he sees her as someone to worry about and keep out of trouble