I know the trick to swap/split lanes of a belt with the underground belt trick.
But I don't use it.
Why? I feel like it's an exploit, like cheating. I feel like it's an ugly way to solve a problem.
Mainly because the art of the underground belts looks like they cannot to that:
That is my feeling.
So, I think you shouldn't remove the "trick", but you could "open" this part of the underground belt where items can pass through.