1mm in premium isn’t an issue. But if you are trading that actively maybe you want a broker that offers DMA like BOB MORSE here. in seriousness, your strategy isn’t worth stealing but consolidating that business can be worth other things (like access to higher end relationship managers or even the private bank or prime brokerage).
To add: if your arbitrage is worth stealing, it’s probably too nuanced to reverse engineer just from seeing your orders.