One way to find such jobs is to network with authors and editors in the fantasy writing community. They might know of available positions or be able to recommend you. Another option is to follow relevant social media groups or forums dedicated to fantasy literature, where job postings might pop up.
I think one reason could be that there's a shortage of good writers, so even the not-so-great ones get opportunities. Also, sometimes a bad writer might have a unique idea that catches the publisher's attention, despite their writing skills not being up to par.
One way to get jobs as fiction writers is to establish an online presence. Share your stories on blogs or social media to build a fan base. Enter writing competitions to gain recognition. And don't forget to continuously improve your storytelling abilities.
One way to find comic colorist jobs is to network within the comic community. Attend comic conventions and workshops to meet potential employers or get referrals. Another option is to create a strong online portfolio and promote it on social media and relevant art platforms.
You can start by checking out specialized job boards for graphic design and illustration. Many of these list freelance opportunities for graphic novels. Also, follow relevant companies and studios on social media as they often post job openings.