I always assumed that most brokers manage stop orders internally and only send them to exchanges/MMs once triggered. Certainly I would expect this from reputable ones like TDAmeritrade. If I understand below article correctly, they are sent to MMs before triggering. Which means MMs actually know where the stops are! Someone please tell me it ain’t so.
https://alphacution.com/robinhoods-trailing-stop-orders-extreme-profitability-by-design/
Institutional investors have the upper hand in knowing where other institutional investors stops are at. If they can do that then what makes you think that brokers and exchanges can't??? How many times have you been stopped out while the market is bullish? And it's not only brokers, but also big players looking to make a profit. The markets are rigged, and as soon as you can accept the fact that they are then you will become a better trader.