Hey there,
Sometimes the embedded <iframe> doesn't work. Here is a potential solution:
I've attached a currently-working code. You should put this at the top of your file (even outside the <style> tag) so that it works properly (and you can go back and fix quickly should you need to.) Remember to fill in with your own ID and delete the brackets.
Note that the below code works with YT playlists only, but you can obviously add a single song if you just want one. If you don't want this to loop, change loop=1 to loop=0.
Paste the following in your About Me section (Ctrl+C this code then Ctrl+Shift+V):
<iframe width="0" height="0" src="https://www.youtube.com/embed/playlist?list=[your public YT playlist here]&;amp;;autoplay=1&;loop=1&;controls=1" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen="" loading="lazy">
</iframe>
If the above doesn't work, it might be because of rate-limiting (though I'm not a specialist, I just happened to run into the same issue, and it gets resolved after a day or so.) You can test this by replacing it with a different public playlist - it usually works.