Orderfill probability when arbitrage with limit order

Hey everyone!

I'm running a cross-exchange market-making strategy that arbitrages with limit orders. The issue I face is that sometimes my order on the second exchange doesn’t get filled, and the price moves away. To handle this, I’ve set up a kind of "stop-loss": if the order isn’t executed, I cancel it and take a market order to stay delta neutral (I hedge with a perp).

I'm trading in the crypto market—any ideas on how to improve my system?