Report builder: Use this only if you want to feed small amount data.
Data warehouse: This is the option I would recommend if your data is not live streaming. Calculated Metrics can be extracted via ETL process but the gap is that pathing metrics (entries, exits, bounces, etc) are not available in data warehouse.
So if you need pathing metrics, you should go with data feed.
Datafeed: This is most robust way of data extraction. Data feed is the just raw variables in a Server Call and you have to calculate all the metrics(Including calculated metrics) manually through ETL. Below the link on how the calculation is done : Calculating Metrics. I am not sure whether ETL will do everything in a perfect way.
Also, if you are planning to integrate Tablaeu with Adobe Reports and Analytics, can you check the connector Cognetik : https://www.cognetik.com/cloud-tableau-connector. It is free tool with limited capabilities. If needed, you can check for premium version.