iPhone 15 iOS 18.6 contact poster not showing??

All the numbers on my device are correct and of course, my device is connected to my iCloud account. I just bought the phone a few days ago. It has iOS 18.6, and the software is up-to-date and working fine.

However, when I call someone, the contact cards of that iPhone don't appear; that is, any photos they've added to their contact cards don't appear. Similarly, my contact card doesn't appear on theirs. As you know, when you stack two iPhones on top of each other, their contact cards appear (only their names appear, but no photos) I'm also experiencing a similar issue when I try to use iMessage with someone else.

Also, all the settings required for this feature to work are enabled and I have created my own contact card.