the code i used was this:
<iframe width="0" height="0" src="{insert yt link here here}/?&;amp;;autoplay=1&loop=1&;controls=1" title="{just put whatever title here}" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen="" loading="lazy">
</iframe>
u can insert it in whatever box in ur profile i think when u edit it, but i put mine in the general box. the yt link should be an embed link iirc, so just click on the video and press share then the embed option (ex. https://www.youtube.com/embed/2ai5NWd8nuo?si=3zhQP8MdsVr7pOiv)