Recent posts at the height of the article featured image

Hi there,

in your Customizer > Additional CSS you have this CSS:

.separate-containers #page .site-main {
    margin-top: -80px !important;
}

Delete that. This will vertically align the sidebar and the post content.

If you want to reduce the space between the hero title and the content/sidebar.
Then edit the Page Hero Block Element in Appearance > Elements ( or when viewing the page Admin Bar > Elements menu ). Select the Container Block and reduce its Bottom Padding.