Change Gravity Forms submit input to button element

gravity-forms-mods.php

<?php

/**
 * Change submit form <input> element to <button> element for AJAX enabled forms
 *
 * @link https://docs.gravityforms.com/gform_submit_button/
 */
add_filter( 'gform_submit_button', function ( $button, $form ) {

    $dom = new DOMDocument();
    $dom->loadHTML( $button );
    $input = $dom->getElementsByTagName( 'input' )->item(0);
    
    // Skip for all except submit button
    if ( 'submit' !== $input->getAttribute('type') )
    {
        return $button;
    }

    return sprintf("<button type='%s' onclick='%s' onkeypress='%s' id='%s' class='%s'>%s</button>",
        $input->getAttribute('type'),
        $input->getAttribute('onclick'),
        $input->getAttribute('onkeypress'),
        $input->getAttribute('id'),
        $input->getAttribute('class'),
        $input->getAttribute('value')
    );
}, 10, 2 );