Replace post publish date with custom field

Hi,

You can use an MB action to update post data, for example rwmb_{$meta_box_id}_after_save_post.

add_action( 'rwmb_versionning_after_save_post', 'update_post_title' );
function update_post_title( $post_id ) {
    // Get the field value
    $my_meta = rwmb_meta( 'field_date_id', '', $post_id );
    
    // Preprare update post
    $my_post = array(
        'ID' => $post_id,
        'post_date' => $my_meta,
    );
    wp_update_post( $my_post );
}

Refer to this topic https://support.metabox.io/topic/adding-metabox-field-data-to-the-post-title/#post-34119
and WP documentation https://developer.wordpress.org/reference/functions/wp_update_post/