The most frustrating thing about this is that I’ve done a lot of homework and talked with a number of builders. I always start with full disclosure about what I want
My advice is: Don't expect that you are being heard and understood just because you are talking. Your garage is not typical or simple, but its human nature to assume (even though you are saying different details) that your garage is just like 95% of all the others out there. If it was, you'd have no problem at $30K.
They then go away for weeks to draw plans and collect bids and then come back with estimate 2 to 3 times where we started – WTF!!!
Your expectations are way off. I don't know where the $30K number came from, but you'll be lucky to purchase all the materials you need for that price. (Including the material that you are going to install, yourself.) Once you add in the heavy equipment, labor, and profit for the parties involved, you will end up far north of that figure. (If you are under 15% for GC fees on a custom-designed structure, you are in good shape. If a contractor tells you that they charge much less than that, they won't be in business long or they account for some of their expenses under other line items.)
I'd say that you could pull off a garage for $75/sq. ft. if it was basic. (A 20X20 "typical" garage would put you at $30K at that point.) Since your garage is extra large, extra tall, skewed, attached, complex roof geometry, etc. you are going to come in at least $100/sq. ft. - and maybe more. (Finished houses cost much more than that but one thing to keep in mind is that the exterior walls and roof of any structure are the most expensive part.)
Depending on the level of finish you have spec'd for the inside (finish of drywall, finish of floor, HVAC, electrical, etc.) the bids you have may be very good.
Another thing to realize is that your angles make things much more expensive. Based on my recent experience designing a triangular shaped house, (we had to completely scrap the design and pay the architect to do a completely new, more rectangular, design) I'd guess that you are paying a 10% premium off-the-bat for your angled walls. The price starts shooting up once you get away from a perfect square or rectangle. To illustrate this:
100 sq. ft. circle = 35.5 linear ft. of wall
100 sq. ft. square/rectangle = 40 linear ft. of wall
100 sq. ft. triangle = 60 linear ft. of wall
Your size, height, and architect aren't doing you any favors. If you changed to a rectangular garage, aligned to the house, with a simple hip roof, you could get the price way down - but it would still be higher than $30K. I'd guess that your architect's design (which is striking) is costing you an extra $10-20K on construction costs. (Your architect will tell you that you can't put a price on design, but your contractor certainly can!)
BTW - If your architect let you to believe that this was a $30K design and you've paid them in full, you may want to reach out to a lawyer!