hi,
To remove the text from the activity delete button and replace it by an icon, I inspected bp-activity-template.php file, and in line 2616 there is the function bp_activity_delete_link() called in entry.php file, and the hook bp_get_activity_delete_link.

function bp_get_activity_delete_link() {

		$url   = bp_get_activity_delete_url();
		$class = 'delete-activity';

		// Determine if we're on a single activity page, and customize accordingly.
		if ( bp_is_activity_component() && is_numeric( bp_current_action() ) ) {
			$class = 'delete-activity-single';
		}

		$link = '<a href="' . esc_url( $url ) . '" rel="nofollow">' . __( 'Delete', 'buddypress' ) . '</a>';

		/**
		 * Filters the activity delete link.
		 *
		 * @since 1.1.0
		 *
		 * @param string $link Activity delete HTML link.
		 */
		return apply_filters( 'bp_get_activity_delete_link', $link );
	}

To remove the text of the button, I created this function whith the sample of the original hook

function yoostart_remove_activity_delete_text(){
    $url   = bp_get_activity_delete_url();
    $class = 'delete-activity';

    $link = '<a href="' . esc_url( $url ) . '" rel="nofollow">' . __( '', 'buddypress' ) . '</a>';
    return $link;
}
add_filter('bp_get_activity_delete_link', 'yoostart_remove_activity_delete_text' );

it’s work, but i’m beginner and I would like to know if this function isn’t likely to create errors

thank you
Ahmed