reference: Reliable pipeline to import contacts from Google?
I've read this thread with all linked threads/issues because I was also looking for a solution to get my contacts from Google to my NextCloud server.
At the moment I use NextCloud 20.0.14 and Contacts 4.0.8.
Sure, you are able to export from https://contacts.google.com but there you have only three options:
1. Google CSV
2. Outlook CSV
3. vCard (for iOS-Contacts)
While the first two options did not work at all to import to NextCloud (it just told me "... imported 0 contacts .."), the option with vCard basically worked, it could import all contacts. What I noticed at first sight was that this did not take profile pictures so none of the contacts had a profile picture in NextCloud after import.
Then I tried the "Google integration" app in NextCloud but after going through the hassle of setting up the OAuth 2.0-Client-ID at https://console.cloud.google.com/apis/credentials and then connecting my NextCloud account in Settings -> Data migration to Google I got some HTTP/403 errors and did not know how to fix that so I searched further for another way.
Since I imported the vCard contacts from Google, I wanted to delete that newly created "myContacts" group (without profile pictures) but found out, that there is a feature request / issue report and the only working "easy" solution was to do that from my (Android) smartphone using DAVx5 and any installed contacts app. This way I simply deleted this "myContacts" label with all contacts in it and started sync in DAVx5 app. Wonderful.
That got me to the idea to also manage my contacts on my smartphone and sync them to NextCloud. So however your smartphone setup looks like, the process could look a little bit different but basically it boils down to following steps:
1. You need any smartphone where your Google account is configured and synchronized
2. On that smartphone open the Google "Contacts" app - there you are able to **export your contacts as vcf file** (this exports **all details** - also profile pictures)
3. (optional) However your setup looks like, you maybe need to transfer/copy the exported vcf file to another phone where you do not have your Google account synchronized but have DAVx5 installed or want to use your contacts synchronized to your NextCloud server without Google.
4. Install DAVx5 and configure it to synchronize your address book from your NextCloud server.
5. Open the Contacts app of your phone (I tried two different apps, it worked with both of them) and import the vcf file to your DAVx5 synchronized address book.
6. Check your contacts if they are all good, go to DAVx5 and start synchronizing your configured NextCloud account / address book - then look on your NextCloud server if your contacts are all good.
While looking through the web, this thread came up at the first few search results so I hope this "Reliable pipeline" works for others too, for me this was the easiest reliable working way to get the contacts from Google to my NextCloud server.