functions.php

function qorp_about_block_template_lookup( $template, $type, array $templates ) {

	if ( $template && 'page-about.php' === $templates[0] ) {
		add_filter( 'the_content', 'qorp_append_post_meta_output' );
	}
}
add_filter( 'page_template', 'qorp_about_block_template_lookup', 20, 3 );

function qorp_append_post_meta_output( $content ) {
	ob_start();
	get_template_part( 'template-parts/team-members' );
	$team = ob_get_clean();

	return $content . $team;
}