iPhone 13 Pro from USA malfunctioning

Hello, I have an issue regarding two iPhone models, more specifically the iPhone 13 Pro (USA version according to decoding in the menu) and the second one is the iPhone 13 Pro from Polish distribution. The phone from the USA was bought from a company on an auction website as an exhibition phone, the iPhone from Polish distribution was bought in an electronics store.

The problem is that the phones are the same, but they work completely differently. An example is that the US iPhone works slower than the Polish one. Both phones are not "cluttered". Another problem is that, for example, during a conversation in the US version, you cannot enter an application because the phone will simply hang sometimes. This has also been tested on a Polish phone and it works without any problems.