Well, I’ll admit it might be poorly suited, but I know it supports comments, posts, and user signups. Users would sign up with a sbscriber role, you’d verify them somehow, and then you’d update their role. It would be a little janky but should work with little adjustment

Easiest? I’d say WordPress on a Digital Ocean droplet if you’re going super small. Allow people to sign up and vet them, and you have a functional standalone platform pretty much as soon as you can get users. I don’t know that it would take off or have a sustainable userbase though