Hi there,
to remove just the copyright you can use this PHP Snippet:
add_action( 'after_setup_theme','db_remove_credits' );
function db_remove_credits() {
remove_action( 'generate_credits', 'generate_add_footer_info' );
}
Although Elvins recommendation to completely remove the footer bar and you can use a Hook or another widget to add your floating link would make more sense. This article explains how to remove the footer bar:
https://docs.generatepress.com/article/changing-the-copyright-message/#removing-the-entire-footer-bar
The space below the footer bar is the body background as the page is not long enough to fill the height of the screen. I provide some CSS to force the footer to the bottom of the page:
https://generatepress.com/forums/topic/cant-get-menu-nav-or-footer-to-be-sticky/#post-1232453
But this will just move the empty space above your footer widgets.