I'm trying to book a flight with a decent price via Google Flights, but the flight ranking by price is messed up due to Google Flights showing the minimum price one can obtain, which often comes from travel agencies. But travel agencies often don't have that price anymore and/or take a long time to issue the ticket (and the ticket booking may eventually be unsuccessful after x days, when prices have doubled or after when the passenger wanted to start traveling).
How can I configure Google Flights so that it only shows prices from airlines and not the travel agencies?
The Separate & self-transfer tickets option looked promising, but it doesn't seem to hide prices from travel agencies: it only hides flights that can only be purchased via a travel agency, which doesn't entirely solve my issue.