Add this file into a Framer X project to load a script to the top of your project

AddScript.js

function Loader() {
  if (document.getElementById("customScript")) {
    console.log("Script is already loaded!");
    return;
  }

  const script = document.createElement("script");
  script.src = "path/to/sript.js";
  script.id = "customScript";
  document.head.appendChild(script);
}

Loader();