Here's the final improved version:
// ==UserScript==
// @name Chrome Force Dark Mode Fix/White Overlay Fix
// @namespace namespace
// @include *://www.youtube*
// @description Fixes Chrome Force Dark Mode on YouTube
// @grant GM_addStyle
// @grant GM.getValue
// @require http://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js
// @require https://gist.github.com/raw/2625891/waitForKeyElements.js
// ==/UserScript==
waitForKeyElements ("div.ytp-gradient-bottom, div.ytp-gradient-top", removeNode);
function removeNode (jNode) {
jNode.remove ();
}