It looks like the order event was not tracked because of incorrect value type of product ID.
The dataLayer value is indeed an integer but you should send a string there (id field):
{
"id": 4420,
"name": "Zahradní okrasný plastový plot 2,2 m",
"category": "Ploty/Plastové ploty",
"brand": "Ostatní",
"quantity": 1,
"price": 319,
"priceWithoutVat": 263.63636,
"long_id": 297493127
}