Issues Migrating Mixpanel Mirror Events to New Project and Missing Mirror Sync Option

We've decided to switch entirely to Mixpanel's event SDK for our customer web app and our marketing website. We previously used Segment's event SDK on just our customer web app and Mixpanel's event SDK on the marketing website. I've created a new project called New Production which is receiving events from the Mixpanel event SDK calls on the customer web app. I now want to migrate the existing mixpanel mirror events from my warehouse to the new project. I've setup a service account in the same way as I did before however I'm not seeing the option to use mirror syncs on this setup... What am I doing wrong or does something need enabling on your side?