So, I am playing Nakalim and I over just a few turns - maybe 4 - go from stockpiling 90K+ Dust to being eliminated by going minus on dust.

I look at what gives me the minus values:

Systems.

- I have done developments with Dustcidious Trees so if anything... I should be making a lot of money. I have also put aaaaa loooooot of money into my trade routs. In addition, several of my systems 5-6 of them with 20-26 population in each just got Level 4 development with Dustcidious Trees and Proto Orchid; that should make my economy go even more boom... but instead it goes the other direction.

Citadel

- And somehow my Citadel that I just got costs -24000 ish per turn!?

- My ally AI has like 5 Citadels..... !??!

And there is some weird "Cravers war funding -10000" if I read it right... I couldn´t find it when I went back into the saved previous turns.

Only thing I can think of that made the citadel be expensive is that I built several of these "increase your behemoth bulding cap" buildings.

But how can this suddenly take me from 90K to going minus 40K per turn???

I think you should read tech descriptions more carefully

Problem isn't that you have 8 Behemoths (assuming you've listed all your 6 science Behemoths, Citadel and Juggernaut). Problem is that you've built too many C3s for no reason.

Every time you build it in system, you increase your total upkeep of all Behemoths by 150%. And for what? For +1 limit? You don't need 20 Behemoths limit, when you actually have only 8.

You can have a limit of up to 7+ Behemoths from just researching Behemoth technologies, then up to 10+ by building couple C3s. Base Behemoth upkeep is very small, like 96 or something, can't remember. So you probably have built at least ten C3s to reach upkeep that high as you have.

Open Constructed Improvements and start scrapping Behemoths C3 Centers, until upkeep becomes manageable.

You can basically scrap all of them, and end well above limit. Then you can keep using your Behemoths, but you won't be allowed to build any new, until you raise your cap back to have a free slot. By capturing systems with Citadels you also adding them to your used slots, as they are now your Citadels.