Suggestion for application caching

It's Oracle 19C. We have one third party app query in which the results out of the query(which is ~300million rows) gets fully cached by the app servers for certain requirements. (Mostly because the other queries on top of those cached result sets are required to be having a very fast response as per business requirement).

And that query executes multiple times each day i.e. once for each app server to cache the result sets. So currently during cache refresh/invalidation, four app servers executing the query each once i.e. four instances of the same query fired on the database simultaneously from four different sessions. The number of app servers is going to be increased to ~12 in future, which means this query is going to be executed 12 times. For each execution , this query takes ~20GB temp space and runs for ~20minutes(~5minutes in database and rest of the time for fetching the rows to the application/client).

The issue which we are trying to address is , This query consumes ~20GB of tempspace for one execution and for 12 servers we will need ~240GB of temp space for those ~20 minutes of duration. Are there any other options out there to handle such a scenario?

Below is the sample query and its sql monitor(in the github link). I have replaced the actual names with dummy names and also just posted the basic skeleton to keep it simple here.

This query has five "UNION ALL" conditions and the TEMP SPACE is spilling while applying the DISTINCT clause mostly. But the application team is resisting that they can't get rid of the "DISTINCT" clause because of current design and also the UNION ALL is from multiple tables with different Join criteria. Also only the specific columns are exposed out of the query but not all. Is there any other way to minimize the tempspill here?