Alright, so I've been told to wait until I get the barracks and blacksmith buildings mad before defeating the behemoth. It's either that it gets more expensive or it's more difficult to get things due to an increase in enemy level, but I don't know which.
The only issue is that the RNG gods hate me right now and simply refuse to give me the things I so desperately need.
I can't seem to get any worn charms (27/60), the last 3 peerless rapiers, and the last 5 silver ores.
Not even going to talk about the tracking grounds- the dang ferrikkis won't give me their orbs.

So, is it really worth waiting?
I've been stuck on stage 5 for a good few weeks and I'm losing interest, but I also don't want to later regret my decision to go ahead if every building suddenly needs twice the amount of materials to make.

I don't believe anything gets more expensive or that the drop rate changes. But the level of every enemy, including elites and bosses, goes up, therefore making it harder to win each fight.

I so wish I could send you extra stuff to help out. :\ I have a bunch of extra materials.

Given that you have a lv70 partially ranked max stat team... honestly, you should be fine. You probably will notice the difficulty increase, especially with bosses. But that's a solid team that should be able to handle itself just fine. No point staying behind at that point.

That said, I do recommend building the blacksmith at some point. Most buildings are hit or miss depending on what you want out of the grove; like I personally don't use the tracking grounds at all, other than doing its tasks. (Some people do find it useful in conjunction with a perfume though.) But the trading post and blacksmith are honestly really useful. Trading post lets you buy healing items with materials rather than gold, and blacksmith allows you to craft and upgrade equips. Very worth it imo. But you don't strictly need them before you progress.

(Also, it amuses me that your lighs are named after pasta.)

Thank you so much!

I spent a bit too long deciding which pasta to name each after :P