Was it something like this you had in mind? Or something more clever with regards to loading the Vite script? With the below it doesn't execute the remote script until later

js
const myTestModule = 'myTestModule';

angular.module(myTestModule, []).config(function() {
  console.log("loader started");
  
  let script = document.createElement("script");
  script.type = "module";
  script.src = "/backoffice/src/main.ts";
  document.getElementsByTagName('head')[0].appendChild(script);
  
  console.log("loader finished");
});

angular.module('umbraco').requires.push(myTestModule);