Create shortcode for APA citation format

Hi, I have created a code to be able to cite with APA format. Without the plugin it can be created fine, but when I install the plugin I can’t get Last name, I. The function get_multiple_authors(); takes me the full name of the authors, if I add initials, it repeats them. The actual citation I get is:
Geraldine Trujillo (December 19, 2023). Predatory and unreliable journals, publishers and metrics. Paideia Studio [Blog]. https://paideiastudio.net/revistas-editoriales-metricas-predatorias/.

When it should be:

Trujillo, G. (19 December, 2023). Predatory and unreliable magazines, publishers and metrics. Paideia Studio [Blog]. https://paideiastudio.net/revistas-editoriales-metricas-predatorias/.

The same thing happens in Multiplautores. I don’t have a published example yet.

The code is:

// Nuevo shortcode personalizado [mi_shortcode_cita]
add_shortcode('mi_shortcode_cita', 'mi_shortcode_cita_func');

function mi_shortcode_cita_func() {
    // Obtener datos necesarios para la cita desde la publicación actual
    $authors = get_multiple_authors();
    
    $author_parts = array();

    foreach ($authors as $author) {
        // Obtener el nombre completo del autor
        $author_name = $author->display_name;
        
        $author_parts[] = $author_name;
    }

    $authors_str = implode(' & ', $author_parts);

    $publication_date = get_the_date();
    $title = get_the_title();
    $sitename = get_bloginfo('name');
    $permalink = get_permalink();

    // Construir la etiqueta de cita según el formato deseado
    $cita = sprintf(
        '%s. (%s). %s. %s [Blog]. %s.',
        $authors_str,
        $publication_date,
        $title,
        $sitename,
        $permalink
    );

    // Agregar el botón de copia al portapapeles
    $cita .= '<button class="btn-copiar" data-clipboard-text="' . esc_attr($cita) . '" style="background: #f7f7f7; color: #7DC22B; border: none; cursor: pointer; font-size: 14px; padding: 8px 16px; position: absolute; top: -35px; right: 0; z-index: 1;">Copy</button>';

    // Agregar el script JavaScript para Clipboard.js utilizando wp_add_inline_script
    $cita .= '<script src="https://cdnjs.cloudflare.com/ajax/libs/clipboard.js/2.0.8/clipboard.min.js"></script>';
    $cita .= '<script>
        document.addEventListener("DOMContentLoaded", function() {
            new ClipboardJS(".btn-copiar").on("success", function(e) {
                alert("Texto copiado al portapapeles");
                e.clearSelection();
            });
        });
    </script>';

    return '<div class="mi-cita" style="color: #000000; position: relative;">' . $cita . '</div>';
}

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