Have you reviewed the documentation with regard to API keys on the platform here https://developers.arcgis.com/documentation/mapping-apis-and-services/security/api-keys/? Though given your workflow, i'm not sure the keys will work.
The other potential solution for your issue is to look at using application authentication with your processing results. Using a client id and client key, you can generate token. The token can then be used to interact with the platform, there are some limitations with that approach, the account/owner associated with the client id and secret application. https://developers.arcgis.com/documentation/mapping-apis-and-services/security/app-credential-authen.... Note this does stare you cannot publish a layer.
However, my question would be could you create a single hosted layer a push your new features in to this layer? Perhaps adding a field to assoicate the analysis with the current logged in user or some other unique identifier for the results to then filter the analysis. If you are constantly generating hosted feature layers, then you would need some kind of management/governance around all those layers.
Again, I don't know the full workflow, but there are perhaps some others that it could be solved, and there are some other authentication methods in the docs I have linked too. The above approach with application authentication is one we are using in an integration context where we have members of the public working with a map embbed in a third party application to update features in to ArcGIS Online.
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