const targetNode = document.body;

const config = {
    childList: true,
    subtree: true
};

const callback = function(mutationsList, observer) {

    const container = document.querySelector('ytd-page-manager #player-container');
    if (!container) {
        return;
    }
    container.addEventListener('pointerdown', (e) => {
        e.stopImmediatePropagation();
    }, true)
    observer.disconnect();
    console.log('yt done');
};

const observer = new MutationObserver(callback);

observer.observe(targetNode, config);