osr-discourse-src/app/assets/javascripts/discourse/routes/restricted-user.js

import DiscourseRoute from "discourse/routes/discourse";

// A base route that allows us to redirect when access is restricted
export default DiscourseRoute.extend({
  afterModel() {
    if (!this.modelFor("user").get("can_edit")) {
      this.replaceWith("userActivity");
    }
  }
});