This is an issue with the size setting options of the web embed component. This empty area becomes even more pronounced when the view is seen on mobile. Furthermore, you will find that these size setting options do not work when placed within a container. If you do not place it inside a container, you can still use these size settings, but it is also pointless if this size is not responsive in mobile view.
I have raised this issue before, but there are no signs of resolution yet.