Can’t transfer my data to my new iphone

I bought a Iphone 13 Pro Max with 256Gb storage and my old iPhone X Pro Max with 512Gb ( but only 127Gb is being used, and 385Gb storage is not used). When I transfer the data to the new iPhone, it said that the data transfer cannot be completed since my new iPhone doesn’t enough storage.

please advise why? I consult the shop keeper before make the purchase, he said I just need a 256Gb is enough. So disappointed with this experience.