Is it possible to somehow see what the editor is doing when I hit Play, until something actually happens?
I’m not quite sure what I did, but I got an extra 20 seconds added to the start time today.
At the top of unity go to “Window → Analysis → Profiler”. Normally, this tool will tell you what is happening and how much time function calls are taking in your game, but you can select “Profile Editor” at the top to have it report this info about the Unity Editor instead of your game code.
It’s worth noting that the Unity Editor will pause to load resources as soon as they are needed, which can cause large pauses when new assets are revealed for the first time in a run. This pausing to load resources does not occur in a build unless you manually load a large resource.