PHPStan Level 5 Fehler

Beim Ausführen von PHPStan auf Level 5 gibt es die nachfolgenden Fehler.
Die Fehler wurden ersteinmal in die Baseline übernommen.
Bitte die Fehler sichten und die wichtigsten beheben.
Möglicherweise sind die Fehler nicht mehr aktuell, daher besser PHPStan ohne Baseline selbst ausführen.

• src/QUI/ERP/Order/Guest/EventHandler.php:165:Method QUI\ERP\Order\Guest\EventHandler::onOrderProcessGetOrder() should return QUI\ERP\Order\OrderInProcess|null but returns QUI\ERP\Order\Order.
• src/QUI/ERP/Order/Guest/EventHandler.php:267:Call to an undefined method QUI\ERP\Order\AbstractOrder::save().
• src/QUI/ERP/Order/Guest/EventHandler.php:288:Call to an undefined method QUI\ERP\Order\AbstractOrder::save().
• src/QUI/ERP/Order/Guest/EventHandler.php:344:Method QUI\ERP\Order\Guest\EventHandler::onQuiqqerOrderClear() with return type void returns null but should not return anything.
• src/QUI/ERP/Order/Guest/EventHandler.php:366:Call to an undefined method QUI\Interfaces\Users\User::getGuestOrderId().
• src/QUI/ERP/Order/Guest/EventHandler.php:455:Class QUI\ERP\Shipping\Order\Shipping not found.
• src/QUI/ERP/Order/Guest/EventHandler.php:539:Method QUI\ERP\Order\Guest\EventHandler::extendMail() with return type void returns null but should not return anything.
• src/QUI/ERP/Order/Guest/EventHandler.php:770:Call to an undefined method QUI\Interfaces\Projects\Site::getUrlRewrittenWithHost().
• src/QUI/ERP/Order/Guest/GuestOrder.php:211:Parameter #1 $groupId of method QUI\Interfaces\Users\User::addToGroup() expects int, string given.
• src/QUI/ERP/Order/Guest/GuestOrder.php:248:Parameter #1 $groupId of method QUI\Interfaces\Users\User::addToGroup() expects int, string given.
• src/QUI/ERP/Order/Guest/GuestOrder.php:277:Parameter #1 $code of method QUI\Interfaces\Users\User::activate() expects string, false given.
• src/QUI/ERP/Order/Guest/GuestOrderUser.php:116:Parameter #2 $User of class QUI\ERP\Address constructor expects QUI\ERP\User|null, $this(QUI\ERP\Order\Guest\GuestOrderUser) given.