I’m lucky enough to have a pair of 27 inch displays at home, and ever since I got the 2nd one I’ve had them arranged coplanar with each other. However, there’s no healthy distance to sit from a pair of 27 inch displays where that makes sense. It looked nice on my desk, but in reality it didn’t help me see the edges very well. A slight angle for each one, such that a slight turn of my head has me facing one head on, is much much better.

Worse to look at as an object, but much better for actually using them.