Mac Mini 2018 maximum carry weight? What is the maximum weight of "stuff" that I can place on top of a 2018 Mac Mini without damaging it?

This is not the weight of the unit itself — but the maximum weight of other units that can be placed on top of it to save desk space. I'm thinking to put a monitor on it (literally).
Apple officially stacks 4 on 1. So at least 4*1.3kg=5.2kg I thought.