Update old data from csv python

I have a bunch of indices A,B,C,D containing large amounts of data per each let's say 50 million records per index and the record contains data as follows:

 user: amine, age: 22, state: Michigan

and I want to create a new index E and bulk new data into it from a csv file. What I hope for is that if a user from E already exists in one of the other indices but with different information for example:

  user: amine, age: 25, state: California 

I want the user amine to be updated in all other indices with the new data.

Create index alias for all indices with writing index targetting E. Update by query , with query identifying the document of the user and doc as upsert parameter, will update the document if exists and create a new document to E if not exists.

You may consider using data stream if you have such situations some times.