Working with IB in Backtrader, you are not exposed to IBpy API at all. Even more , the strategy code should not even know what broker it is working with or even whether or not the broker is live or simulated.

So even if in the future, the IBBroker implementation in Backtrader will switch from IBpy to native TWS python API or IB-insync library - it should have near zero impact on your code anyway.