I got this answer from Adalo support “Unfortunately we aren’t able to provide the Keystore files for makers at this time.”
They also explained we no longer need the keystore file for .aab files (since August 2021), but to upload my non-adalo app with the existing bundle id, that I needed to contact GooglePlay for them to change the uploading key to one we generated. Once the request is validated by Google, it takes 48h for the new uploading key to be valid, during which no APKs can’t be uploaded.
The request can be made following the answer of this stack overflow post