Tapermonkey Script to hide 100% watched youtube videos from a YT Channel.

hide-watched-videos-yt.js

// ==UserScript==
// @name         Hide Watched YouTube Video
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Hide YouTube video when progress bar width is 100%.
// @author       NumeroCuatro
// @match        https://www.youtube.com/*/videos
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    // Function to hide videos with 100% progress bar width
    function hideCompletedVideos() {
        let progressBars = document.querySelectorAll('div#progress.ytd-thumbnail-overlay-resume-playback-renderer');

        progressBars.forEach((progressBar) => {
            if (progressBar.style.width === '100%') {
                const videoContainer = progressBar.closest('ytd-rich-item-renderer');
                if (videoContainer) videoContainer.remove();
            }
        });

        if (progressBars.length <= 0) clearInterval(interval);
    }

    // Check for completed videos on page load
    const interval = setInterval(hideCompletedVideos, 1000);
  
    // add this to the video URL to start watching them chronologically from there
    // &list=ULcxqQ59vzyTk
})();

Don't work anymore and won't bother to see why.