ETL flow for taking data from a remote service, transforming it to a local ORM Model, then setting up relationships?

Question

I recently set up my first "etl" flow to take data from a remote service, modify it to fit my local models, then save it. Now that I've finished, it feels rather grotesque for a few reasons

my source is the JSON from the remote service

my transform replaces each row with a newly defined local model, based on the original source row

transform also looks at various values and defines additional local relationships

destination then calls .save on my newly replaced rows which are now models in the ORM.

1. How am I supposed to create local records based on an external datasource? My models don't look like the remote sources. Is it right to supplant a row entry with my new Model object?
2. If I am supposed to replace the value of row with my local model, then I presume I should split each subsequent action into a transform on that new row (now a model)?

In all, my .etl looks like

pre_process do
  @some = <Go To DB and fetch data>
  @variables = <Setup More Information>
end

source MyRemoteSource

transform DoABunchOfWork,@some,@variables

destination CallSaveOnModels

DoABunchOfWork class has about 6 methods that process will call to manipulate or setup relationships in various ways