Need suggestions on my Runescape copycat game made with UE4

Current state of my game
https://imgur.com/a/vZCuDyE

Hello everyone, so I am trying to replicate Runescape using the powerful tool Unreal Engine 4 but I'm kinda lost and need some suggestions on what features to implement.

Features I have now are:
- Ability System
- Inventory and Equipment System
- Resources gathering
- ????

What else am I missing?

Feel free to send your suggestions guys. Would love to hear that from you, if ever you wanna work with me just send me a private message.

PM ME ! i can help you with materials

Features need :

GUI
UI
Characters
Skills