I was sorting out your game client and drew attention to an interesting case. You are loading a huge dataset on page reload, eating up traffic.
This is one example - initializing the chat window.
Such data will never change in life, but every time your server scoops it out of the heap to give it back.
I can offer you the perfect solution for this - indexeddb. You put data into the browser database once and forget about it forever.
Suitable for such data are chat, buildings, planets, companies, workforce, materials.