crystalndevr

I wanted to update this with an answer that seemed to finally worked for me …. the options_cb didn’t seem to work but actually calling the function then wrapping the name and value data within their own arrays:

array(
    'name'    => 'Select Assistant',
    'desc'     => "The assistant's name",
    'id'          => 'mts-assistant',
    'type'      => 'select',
    'options' => show_assistant_options(),
),

// Callback function

function show_assistant_options() {
	$titles = [];
	$query = new WP_Query(
		$array = array(
			'post_type'                 => 'team',
			'status'                       => 'publish',
			'ignore_sticky_posts' => 1,
			'posts_per_page'       => -1,
			'category_name'        => 'mts-assistant'
		 )
	);
	if ( $query->have_posts() ) {
		while ( $query->have_posts() ) {
				$query->the_post();
				$titles[] = array(
					'value' => get_the_id(),
					'name' => get_the_title(),
			);
		}
	}
	wp_reset_postdata();
	return $titles;
}