Chrome plugin content script cannot access all window objects?

I’m trying to fetch an object from the current page window via a content script. The object itself is available if I log the window/this object but when I try to access it via the content script it returns undefined?

I’m using a content script for this that injects itself on document_idle and via “MAIN” world so the js objects of the page are shared with my content script, see manifest.json:

{
  "name": "Hello Extensions",
  "description": "Base Level Extension",
  "version": "1.0",
  "manifest_version": 3,
  "action": {
    "default_popup": "hello.html",
    "default_icon": "hello_extensions.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://example.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle",
      "world": "MAIN"
    }
  ]
}

And here you have content.js:

addEventListener("load", (event) => {
    console.log("loading")
    console.log(window)
    console.log(window.THEOplayer)
});

And the output in console.log:

and then the output of theoplayer is undefined.

I have tried different solutions accessing it via the this object. Without using the addEventListener…

I can’t seem to find a way to access this object. Even though it seem it’s available in the window it returns a undefined whenever I try to access it via the script. It seems that this object is, one way or another blacklisted from being accessed via my script? But can’t seem to find such a feature via the documentation of the chrome plugin content scripts
. can somebody have a explanation for this and a possible workaround?