Replacing div content with JavaScript – YouTube sidebar

I try to replace “opened persistent” with “persistent” on:

<div id="contentContainer" class="style-scope tp-yt-app-drawer" position="left" swipe-open style="transition-duration: 0ms;" opened persistent>

Any help much appreciated.

So far doesn’t work with the below:

document.getElementById('contentContainer').innerHTML = '';
var h1 = document.createElement('h1'); h1.innerHTML = “persistent; document.getElementById('contentContainer').appendChild(h1);