We can see Google contacts already in the browser, but now you can see the unsaved contacts easily. Google indicates unsaved contacts from mail conversations.
These now appear in the search results in the current Android app. Under “Other contacts”, Google Contacts lists unsaved contact details, especially email addresses from email conversations.
On the server-side, these have now also been activated for the Android app, so that you can now also search for those contacts in the app.
If you have missed the function so far and cannot get it via a current update, you can try installing the current APK file manually.
The contacts can then be found by name using the search function and, if desired, also saved in the contact book.