In my opinion, moreover is also correct. Often, Duolingo does not offer a complete list of possible translations, and does not accept ones that are correct. It's a problem but - I suppose - makes us think. And, therefore, learn. I hope.
i'll disagree because, why not. when proving a point people often use better, much better, way better as deciding different levels of something and way better usually tops them all. So, i wouldn't claim way better is the same.