In the case of using the iPad Magic Keyboard, when an item is blank inside, the two-finger left and right swipe gesture on the trackpad is useless. There is no way to directly call out the sidebar by Two-finger swipe.
We hear you, we’re as frustrated about it as you are. Unfortunately this is because of limitations in Apple’s trackpad APIs. In short, the system does tell us a swipe has happened, but not where it happened on screen. So in contrast to the Mac we cannot determine if you swipe with the pointer near the left or near the right edge of the screen and therefore cannot guess your intention in the way we can on the Mac or when you swipe with your fingers on the screen instead of the trackpad.