hi, rdaka thanks for asking, But I have a question for you that why aren't you using REST Api's of vRO. Please find the below links these would be very helpful for completing your objective
these two links follow two different approaches but the core isthe same as both of them are leveraging vRO api's
Due to security concerns, we do not want applications to directly connect to vRO and execute workflows.
If we cannot get the output parameters from vRA calls, I think we may have to fallback to using vRO REST API.