The key reason here is that the embed may be rendered inside of a column which is narrower than the entire window, meaning that the media query won't produce the right result.
A feature query may also be utilized (e.g. @supports (contain: inline-size) { /*...*/ }) where relevant.
Now that container queries are generally available (caniuse), I suggest that the following logic be updated to use them instead of media queries:
https://github.com/rtCamp/wp-cls-terminator/blob/42b682451985c629c262f3029b5a2c32ffd44cba/includes/class-cls-terminator.php#L49-L60
The key reason here is that the embed may be rendered inside of a column which is narrower than the entire window, meaning that the media query won't produce the right result.
A feature query may also be utilized (e.g.
@supports (contain: inline-size) { /*...*/ }
) where relevant.