How do I stop duplicate contacts on iPhone 15 with iOS 18.3.2?

Hi everyone.

How do I stop my contacts being duplicated? I’ve tried manually linking each duplicate (that works until the next iOS update). There is no option to “View duplicates” underneath My Card, which is what comes up when I look up how to get rid of them.

I have an iPhone 15, and iOS version is 18.3.2