Mac Contacts has entries I didn't add.

For reasons unknown to me, Contacts on my Mac has entries that I did not add myself. Lot of them look like the Contacts app picked them up from the Mail app. Are there settings anywhere that control this? I looked through the Previous Recipients list and deleted those that I did not want in the list, however that did not get rid of the unwanted entries in Contacts. Very frustrating, I've had to edit the contacts database a number of times.

Using the latest version of Big Sur. I don't remember this happening in previous versions of the OS.

Seems like new versions of OS always fix some problems and create new ones...

thanks