Tampermonkey filter to hide YT video buffer and keep only the player and the sound. Useful along with https://unhook.app/ and https://github.com/domdomegg/hideytthumbnails-extension and

yt-channel-video-buffer-hider.js

// ==UserScript==
// @name         YouTube Channel Video Buffer Hider
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       You
// @match        https://www.youtube.com/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=youtube.com
// @grant        none
// ==/UserScript==


const allowedChannels = [
    "dreamscape","CanalNostalgia","kamaitachi","Astrophysics","Inutilismo","MathCaf","CircleToonsHD","iamLucid","PortadosFundos","JamesJani"
]

const niceCss = `
  #movie_player > div.ytp-storyboard-framepreview {
    opacity: 0 !important;
    transition: none !important;
  }
  #movie_player > div.html5-video-container > video {
    opacity: 0 !important;
    transition: none !important;
  }
  #movie_player > div.ytp-tooltip.ytp-bottom.ytp-preview {
    opacity: 0 !important;
    transition: none !important;
  }
  #movie_player > div.ytp-chrome-bottom > div.ytp-progress-bar-container.ytp-drag > div.ytp-fine-scrubbing-container {
    opacity: 0 !important;
    transition: none !important;
  }
  #movie_player > div.ytp-storyboard-framepreview > div {
    opacity: 0 !important;
    transition: none !important;
  }
  #movie_player > div.ytp-cued-thumbnail-overlay {
    opacity: 0 !important;
    transition: none !important;
    display: none !important;
  }
  .ytp-autonav-endscreen-upnext-thumbnail .rounded-thumbnail {
    opacity: 0 !important;
    transition: none !important;
  }
`

function applyStyles(css) {
    const head = document.head || document.getElementsByTagName('head')[0],
    style = document.createElement('style');

    head.appendChild(style);

    style.type = 'text/css';
    if (style.styleSheet){
        // This is required for IE8 and below.
        style.styleSheet.cssText = css;
    } else {
        style.appendChild(document.createTextNode(css));
    }
}

function hideVideo() {
    const videoElements = [
        document.querySelector("#movie_player > div.ytp-storyboard-framepreview > div"),
        document.querySelector("#movie_player > div.html5-video-container > video"),
        document.querySelector("#movie_player > div.ytp-tooltip.ytp-bottom.ytp-preview"),
        document.querySelector("#movie_player > div.ytp-chrome-bottom > div.ytp-progress-bar-container.ytp-drag > div.ytp-fine-scrubbing-container"),
    ]

    try {
        for(const e of videoElements) {
            e.style.opacity = 0
        }
    } catch(e) {
      console.log("Error on hiding YouTube video buffer: " + e)
    }

    try {
        applyStyles(niceCss)
    } catch(e) {
      console.log("Error on apply styles to hide YouTube video buffer: " + e)
    }
}

(function() {
    'use strict';

    const url = new URL(window.location.href)

    const isAllowed = allowedChannels.some(channel => url.search.includes(channel))

    if (!isAllowed) {
        hideVideo()
    }
})();