zopflipng --lossless_8bit --iterations=25 step2.png final_better.png
"PNG to PNG better" sounds like a search engine riddle. After all, why would you convert a PNG to a PNG? Isn't that like re-filling a glass of water that is already full? png to png better
pngcheck -v original.png (Shows chunk types and color depth) zopflipng --lossless_8bit --iterations=25 step2
pngquant 256 --skip-if-larger --output step2.png -- step1.png png to png better
A "better" PNG strips these out.
To make an APNG better , you need to optimize the frame disposal and compression.