It's tricky, but here is a solution.
This code:
<iframe width="100%" height="800px" src="https://www.youtube.com/embed/KJ6joZFlQ54?si=Xwz3C03yIxLgEsC-&autoplay=1&mute=1" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>
replace URL with the embed code on youtube (not the share url). Here:
Working example:
https://florentinginot.com/en/we-are-all-lichens/