Most sites bundle freelance with full-time so there's never a real dedicated focus. If they are freelance sites, they usually are part of a bigger platform that take a cut of your work and/or require you to pay to play.

My goal with this is to provide vetted jobs to vetted freelancers. That benefits both sides of the equation.

Plus, when I started out I was a freelancer full-time. I spent a ton of time browsing all sites and filtering by freelance. That got old fast.