Ask HN: Starting with macOS Development?

What's the best way one could start on macOS development today? With the move from Objective-C to Swift, most of the resources I've come across have been less relevant since they are too Obj-C heavy. And most folks who do work on macOS today have been iOS programmers prior. For someone who's starting on this front for the first time, what would be the best way to start on macOS and potentially carry this knowledge over to iOS in the future?

Looking to hear strategies, resources to use etc.