Gravity Forms: Customize the Submit Button HTML

<?php
if ( class_exists( 'GFForms' ) && ! function_exists( 'scseed_gf_custom_submit_button' ) ) {
    /**
     * Replaces the default <input type="submit"> with a <button> element.
     * The onclick guard prevents double submissions while the form processes.
     *
     * @param string $button Default button HTML.
     * @param array  $form   Gravity Forms form array.
     * @return string
     */
    function scseed_gf_custom_submit_button( $button, $form ) {
        $label   = esc_html( $form['button']['text'] ?? 'Submit' );
        $form_id = absint( $form['id'] );
        return sprintf(
            '<button type="submit" id="gform_submit_button_%1$d" class="gform_button button"'
            . ' onclick="if(window['gf_submitting_%1$d']){return false;}'
            . ' window['gf_submitting_%1$d']=true;">'
            . '%2$s'
            . '</button>',
            $form_id,
            $label
        );
    }
    add_filter( 'gform_submit_button', 'scseed_gf_custom_submit_button', 10, 2 );
}