This iPhone 14promaxplus is unlocked,why I can’t use this for my personal choice of carrier?

I bought this apple14 pro max in the United States just this year. Why can’t I used this when I tried to register for an eSim in my carrier of choice? It said eSim locked to Apple 53. I m having a hard time using this. Apple said it’s unlocked then why I can’t register to my country of choice?