Write Integration Response data to Database using Write Records Smart Service

We have a use case as below:
We fetch the data using an external systems (eg: Servicenow) for few fields, remaining are either manual entries by user. Now can we setup a integration with external system and write the data directly to DB using Write Records smart service or first we save the data using Process model and save in DB and then for updating records we use write records smart service.
option1: External System-->Integration-->ProcessModel (Call integration-->Parse response data to CDT structure-Write to data store entity)-->Records--->UI
option2: External System--->Integration--Write Records-->Save DB

which one is possible and can be implemented. Please advise