Querying for Posts Starting with a Specific Letter in Bricks

Looking to show all posts that begin with a letter, like say A in Bricks?

Set Posts per page to a number that is larger than the total number of posts. Ex.: If there are 100 published posts, set Posts per page to say 200 (a realistic number of max no. of posts that will ever be published).

Then add this in child theme‘s functions.php or a code snippets plugin:

function wpse_298888_posts_where( $where, $query ) {
	global $wpdb;

	$starts_with = esc_sql( $query->get( 'starts_with' ) );

	if ( $starts_with ) {
		$where .= " AND $wpdb->posts.post_title LIKE '$starts_with%'";
	}

	return $where;
}
add_filter( 'posts_where', 'wpse_298888_posts_where', 10, 2 );

add_filter( 'bricks/posts/query_vars', function( $query_vars, $settings, $element_id ) {
	if ( $element_id === 'lgbeyi' ) {
		$query_vars['starts_with'] = 'A';
	}
	
	return $query_vars;
}, 10, 3 );

Replace lgbeyi with the Bricks ID of your Query Loop enabled or Posts element.

Reference

https://wordpress.stackexchange.com/a/298913/14380