For my project to move all my contacts to Baikal (see related articles) it is necessary to bring my google contacts to Thunderbirds Addressbook.
Install Gcontactsync addon for thunderbird:
Create a new Address Book which should be used to import the Google Contacts. Also configure your google-Accont. If you are using app-passowords, you have to generate one in your google account.
I have set the Sync-Type to Read-Only, because I just want to receive the contacts, but not to modify them (also it is more secure if we do some mistakes).
Now you can close the window and click on „gcontactSync“ -> „Sync“ to receive the contacts. They should now be available in your GoogleContacts Addressbook.