OK, so from the url in the picture, here are a few things about the height of the sitewide widget area.
There is an inline style that set a minimum height of 165px. Did you do that? If so, remove it
There is a 25px bottom padding set on the Individual Widget options
There is default CSS on the block used for the content that you can remove by adding the rule below to the theme Global Custom CSS rule box
#sitewide-top-widget-area #content *[class^=”wp-block-“] {margin-top:0;margin-bottom:0;}
There is a default 1em space coming from the Content area setting called “Space between Title and content” set that to zero