I did my best to find a way to replicate this, but after nearly two weeks of trying, I haven't made any progress in replicating the first part, loading into that empty map. Even more unfortunate than me not making a manual save, is that my switch is unmodded, so I can't extract the save at all.

Everything I've thought to do with this is explained in the descriptions of the clips from my switch that I posted onto this youtube playlist.