Astra Theme: Display only last modified date in the post metadata.

functions.php

<?php

/**
 * Astra Theme: Display only last modified date in the post metadata.
 *
 */
function j0e_post_date( $output ) {
	$output        = '';
	$format        = apply_filters( 'astra_post_date_format', '' );
	$modified_date = esc_html( get_the_modified_date( $format ) );
	$modified_on   = sprintf(
		esc_html( '%s' ),
		$modified_date
	);
	$output       .= '';
	$output       .= ' ' . $modified_on . '';
	$output       .= '';
	return $output;
}
add_filter( 'astra_post_date', 'j0e_post_date' );