Apple Contacts in macOS... duplicate entries, duplicate entry notes, no drag and drop, rainbow wheel of death

In Apple Contacts (macOS)... I can't drag and drop a contact into a group in the left. It lets me drag it but I can't drop it into a group. What are groups for if we can't put contacts into them?

My notes in individual contacts have somehow duplicated with some contacts having the same not that I wrote at the bottom duplicated 10 to 20 times. Why?

My contacts are duplicated sometimes 10 times. Why?