ruh roh

Delete this, YouTube will catch on and block this workaround.

Edit: disregard. Here is a custom GreaseMonkey/ViolentMonkey userscript to automatically do this for you:

// ==UserScript==
// @name         YouTube to Embed Redirect (Desktop & Mobile)
// @namespace    http://tampermonkey.net/
// @version      1.1
// @description  Redirects YouTube video URLs (desktop and mobile) to their embed version.
// @author       BaroqueInMind
// @match        https://www.youtube.com/watch?v*
// @match        https://m.youtube.com/watch?v*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    // Extract the video ID from the URL
    const videoId = new URLSearchParams(window.location.search).get('v');

    if (videoId) {
        // Redirect to the embed URL
        window.location.href = `https://www.youtube.com/embed/$%7BvideoId%7D`;
    }
})();