How to dedupe/merge contacts from different sources? I have Google Contacts and Office 365 People both on my iPhone/iPad. Whenever a contact is both on Google and Office, they will appear as two different persons in my iOS Contacts app. If I want to update any information about the contact, it appears that I'll have to do that twice.

Is there a solution to this problem?

Ideally, I'd like to have ALL my contacts on Google Contacts, and merely SOME of them on Office 365 People. I'd like the latter to be in sync with the former. I'd love them to show just a single card per person in iOS Contacts.
Merely partially answering my own question:

First make sure to have Settings &gt; Mail, Contacts, Calendars &gt; CONTACTS &gt; Default Account set to Gmail.

Cards from Office 365 and Google that are of the same person can be edited in iOS Contacts. Edit one contact and, right at the bottom (remove the keyboard) one finds link contacts.... There select the other card. (Press link just once.)

This will put all information of that person in one card in iOS Contacts. However, it doesn't seem to push any information from Office 365 to Google or vice versa. If anyone knows how to do that, please let me know.