Add "Custom PHP" Action as first Action After Submit
Copy this script into the Custom PHP field
if ($ajax_handler->is_success) { // only if no errors in previous verification/actions
$user = wp_get_current_user();
if (!$user || !wp_check_password($fields['pwd'], $user->user_pass, $user->ID)) { // set here the Password field Custom ID
wp_send_json_error([
'message' => 'Your Password is incorrect!', // customize error text
'data' => $ajax_handler->data,
]);
}
}