Comparison was made inside the Unity Editor using 2D lights
The program I used for creating 2D normal maps is SpriteIlluminator
The artworks I used for practicing making 2D normal maps was by Ed Laag at edlaag_art:
Ed Laag's post: https://www.instagram.com/edlaag_art/p/C2jY-heudxO/?img_index=1
Ed Laag's instagram page: https://www.instagram.com/edlaag_art/