How to copy/move contact(s) between two accounts

Oggyo

Looking for a way or app to copy/move contact(s) between two Contacts accounts/providers.

Here is the scenario. I have 4 places where I can save contacts:

The phone storage --> Was empty (see below).
CardDAV account OLD --> This one I need to migrate from. DAVx5 sync is broken.
CardDAV account NEW -->This one I need to migrate to. Empty. DAVx5 sync is OK.
MS Exchange contacts account --> My work-related one. I want to keep it separate as is.

The issue is that CardDAV account OLD sync with the CardDAV server is broken, so it contains the only true copy I have.
So far I tried export/import by built-in function but it doesn't ask me about from/to which account to proceed. Similar experience I got from the app SMS Import / Export after that I ended with all contacts from CardDAV account OLD and MS Exchange contacts merged in the phone contact storage. :(

P.S.
How to clean (delete all) contacts from phone contact storage? There is no select all, just one by one. I'm afraid that cleaning the data of Contacts Storage app will blow away the content of the CardDAV account OLD, too.

Oggyo

davx5
This is the alternative way that I already wrote about:

Oggyo So far I tried export/import by built-in function but it doesn't ask me about from/to which account to proceed. Similar experience I got from the app SMS Import / Export

I'm playing now with Fossify Contacts, which gives the option to select an address book when importing from, and exporting to.

davx5

Contacts apps usually provide a way to export contacts into a .vcf file. Export the contacts from one account that does not sync anymore. Then import it into the empty new davx5 account directly on Android and DAVx5 will upload it on the next sync.

Oggyo

I solved this by using Fossify Contacts export/import (see above) plus some manual work. It also gives me the option to select all contacts to perform a deletion from the wrongly import by the built-in Contacts. Looks like I had to uncheck "Merge duplicate contacts" otherwise deleting a contact form the phone deletes also the same contact from another account. I don't know, might be a bug.

Pretty sure an elegant solution for copying/moving contacts exists. At least GPStore has a lot of apps that claim such.
Anyway, lesson learned. Now I maintain a CardDAV copy in my Thunderbird (laptop) where I can easily drag and drop between multiple address books.