After a page like this is fully loaded https://app.contentful.com/spaces/.../entries/... (an internal customized company page for editing a page on a site), I easily can access elements and text like this from the console:

document.querySelectorAll("p[data-test-id='cf-ui-paragraph']")[8].textContent;

But using the same query in a bookmarklet fails on the very first line -- even after the page is fully loaded.

javascript:(function() {
    var path = document.querySelectorAll("p[data-test-id='cf-ui-paragraph']")[8].textContent;
    //
    //
})();

Uncaught TypeError: Cannot read properties of undefined (reading 'textContent')

This seems to be a common issue but all I've seen here is the fact that it's 'not the same DOM'.

Any wisdom on how to get this (or any query at all) working on a Contentful backend editor page?