In general, brokers are not interested in what you are trading because most traders are not earning money
This is a hunch. Newer brokers that sell order flow has built in functionality in their shiny new trading platform that allows the MM to view the order that you are about to place. Done to ensure lightning fast executions.
No, at least Not on desktop software. The only information that is send to your brokers server is the take Profit, stop loss, and of course at which price you bought. Also pending orders + details. However, on web browser software he is theoretically able to see all of your indicators, setups, etc.
They probably notice very profitable traders, but know them to be statistical anomalies. The eventual reversion to the mean (blow up) is what they worry about.
Why is the concern as long as you are doing everything legit. It is fairly easy to catch suspicious trade. Don't do it.