In priniciple the Simulator App had been designed for exactly the use-case you have. It was developed during an internal project, where we wanted to simulate the behaviour of different devices and then evaluate the result. I have not been using it for a while, though.
The idea is, that you can define a full simulated environment (Meters, ESS, etc.) via a JSON-RPC call and receive the simulation results as a JSON-RPC response. It should also be possible to visualize the results in OpenEMS UI.
The simulated data is not written to InfluxDB; but you receive it as JSON.
See Error response when triggering simulator app through API request and possibly other threads in the Forum also.
Regards,
Stefan