XL macOS runners can now be used by any developer, without the need to sign-up! You can try the new runners today by setting the runs-on: key to macos-latest-xl, macos-12-xl, or macos-13-xl in your workflow file. The runners are available today to all customers!

More information about using the runner can be found here.
To learn more about runner per job minute pricing, check out the docs.