Black Survival uses Google or Apple ID to sign in.
Therefore, you can't just delete the account itself.
If you delete the account, signing in with the linked name will not be possible
(If you add the following account again to your device, you will be able to sign in again)
However, if you are deleting the game to reset,
Due to players playing after reset
New players have suffered due to this problem.
If you add a new account to your device, you can start a new game. Please take note of it.