This example was used when creating a custom Gutenberg block for displaying a single, specific post from a CPT that’s built with ACF.
function custom_field_excerpt() {
$custom_field = get_field( 'custom_field' );
$excerpt = get_field( 'custom_field_excerpt', $custom_field );
$excerpt_length = 20;
$trim = wp_trim_words( $excerpt, $excerpt_length );
return apply_filters( $excerpt, $trim );
}
echo custom_field_excerpt();