There should be an easy way to center objects to each other, along any of the 3 axes.
There is a plugin that does this (JHS Powerbar - module Pixero by Cadfather), but (1) this is really basic functionality that’s common in many layout / diagram programs, really surprised SKP is missing it in core, (2) involves installing a plugin with dozens of unneeded features, (3) workflow becomes dependent on the plugin, and what happens if the developer gets hit by a meteorite from outer space…
