I'm trying to book a flight with a decent price via Google Flight, but the flight ranking by price is messed up due to Google Flight 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.

How can I configure Google Flight 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 travel agency, which doesn't entirely solve my issue.