First, let’s remember the distinction between fidelity (pixel density) and physical size. Nobody has ever suggested starting a macOS app icon at 16×16 and exporting at higher resolutions, because each of those icon resolutions is used at a different physical size.
The majority of the article applies to any screen-based design workflow—whether your design tool is Sketch, Photoshop, Affinity, Figma, or something else. I highly recommend Marc Edwards’s articles, as he has perfected a Photoshop workflow that streamlines working across pixel densities. Look through his articles here.