Restrict WordPress search to a single ACF field

I ended up using a simple meta_query:

$args = [
    'post_status'  => 'publish',
    'post_type'    => $post_type,
    'orderby'      => 'title',
    'order'        => 'ASC',
    'meta_query' => array(
        'relation' => 'OR',
        array(
            'key'           => 'my_acf_field',
            'value'         => $search_term,
            'compare'       => 'LIKE'
        ),
    )
];

$query = new WP_Query($args);