Read More Link with Excerpt

gistfile1.txt

add_filter( 'wp_trim_excerpt', 'tu_excerpt_metabox_more' );
function tu_excerpt_metabox_more( $excerpt ) {
	$output = $excerpt;
	
	if ( has_excerpt() ) {
		$output = sprintf( '%1$s <p class="read-more-container"><a class="ast-button" href="%2$s">Read more</a></p>',
			$excerpt,
			get_permalink()
		);
	}
	
	return $output;
}

/** https://generatepress.com/forums/topic/read-more-button-disappears-when-using-manual-excerpts/#post-476456 **/