shiftscreen comes with 100% mouse/trackpad control.
When the cursor leaves the screen (and still is inside of the shiftscreen app) there will be a white arrow indicating it‘s location outside of the screen.
<aside> 🖱️ Notice: soon there will be more kinds of pointers you can use inside of shiftscreen. (Similar to the normal iPadOS pointer style)
In order to improve your iPad mouse experience when in iPad Split View , you should disable Pointer Animations in the iPad settings. This is important since the separator between the split-view windows will attract and move the cursor when being close to it.
iOS currently does not enable developers to use bluetooth mice and trackpads with the iPhone.
The solution at the moment is to use the iPhone itself as a trackpad. In order to use the iPhone as a trackpad, change the control mode to the "device as trackpad"-mode.