I'm going to second what @Alex Cano said, and add a bit of Prefect context here as well.
Boiling down your requirements, it sounds like you have scripts that need to be run on a schedule. Prefect is great at that! And if you want them to be built from specific repos, I think your best bet is including a step in your CI/CD process that builds/registers your flows with Prefect Server at the appropriate moments. Once registered, those flows can be run on a schedule or manually as you'd like.
I'll echo that you'll need to be careful, security-wise. Prefect Server doesn't include an auth component, so you'll want to make sure that you're not unintentionally exposing an unauthenticated endpoint to the internet. Depending on your setup, that may not be a concern, but definitely worth keeping an eye out for.