Hi. If you are budgeting $2k a square metre you won't get much. My hubby is a builder, we run our own renovations and extensions company. We say to our clients, you are looking at ballpark $3-4k per square metre and that still depends on the finish you are after. If you want high end add more. And that is just for the build, not including drawings/council/engineers/certifiers etc. Often it's $20k before a thing has been built. (Architects alone can be $20k). Subcontractors charge a lot nowadays too ie a good plumber is $100 per hour etc. We generally say to our friends if they are tossing up what to do, go with a project home company. They can buy everything bulk and at cheaper prices. They charge a lot for variations but if you don't change too much from their plans, it's better value for money.
One more thing, in the uk subcontractors get paid a pittance (my hubby worked there for a while), that is why they can do renovations so cheaply over there. You can't compare prices there to here, they don't equate.
Hope this helps 😊