When the Contacts stored in my Disroot account are synchronized (with DAVdroid), the new Contacts I have added in the Disroot cloud, appear on my phone, but not the other way around. How can I synchronize in both directions?
When you create a new contact on your phone you can choose to save it in your DAVdroid-account or “local only”. It different depending on your Android version but I would guess this is your problem.
I use Fairphone Open OS without Google Services and the default Contacts app does not give me the option to save it to Local or DAVdroid account.