Use a private key for all apps

The private key is used to verify and prove that you own the application. Any APK that is uploading to the store must be "signed" by this private key and prove that it is a true build.

For each application you want to send to the PRECISA store, have your private key unique . If for some reason you accidentally lose or delete this private key created to sign your application, you will never be able to go to the store again, having to create another project (different package) and make a new upload, thus losing all downloads, users , evaluations etc.

In other words, if you use the same private key and the same keystore for all your applications, only one of them can go to the store (in this case, the first one you upload).

You can have multiple private keys for the same keystore if this is more convenient for you, there is no problem. But, I particularly prefer to have one for each project separately, with the proper backups done for each one.