How come I can't put anymore harpie ladies in my deck?

I was in the midst of creating a harpie based deck when I realised that there are certain cards that won't fit in if theres about three more of a monster that has the word "harpie lady" on it which explains why I can have three cyber lady and not any of the cards that have harpie lady in the title and vice versa.

Yes if a card has a line such as "this cards name is always treated as" then it follow the max rule of 3 per deck. Since Cyber Harpie Lady is treated as "Harpie Lady" then it follows the official rule of being seen as a "Harpie Lady" card for deck building purposes meaning. You can only have 3 Harpie Lady cards in your deck.