Societies in hot areas like Indiranagar, Koramangala and HSR are mostly always with brokers. It primarily happens as top brokers in each area like to control the price point for these flats to ensure they can milk as much brokerage as they can from people and more than often will end up creating a fake supply shortage.
I suggest finding people who stay in your desired societies and maybe finding a flat via them. Sometimes folks in society groups get to know when a flat is being vacated and you can pounce on it if you like.
I've done the same when finding my last apartment.