Terminate house construction contract? Wrong advice!?

Hello, we signed a contract at the end of last year for the construction of a single-family house. Unfortunately, the ancillary costs were sugar-coated to us even after repeated inquiries. Currently, the construction ancillary costs are over 100% higher than in the initial plan, and the house itself is also becoming increasingly expensive, and this is not due to any extra wishes on our part. Now the question is, if the trust in the company has already been significantly damaged (not to mention the financing of the whole thing), is there a way to get out of the contract? The contract itself is fine, but the advice from an experienced person was just terrible, and there were lies left and right regarding additional costs for the house and especially the ancillary construction costs.

Thank you in advance and best regards

Hello, what was agreed upon regarding the additional costs in the contract? If nothing, are there any other written agreements or protocols?! If also nothing, it will result in an unpleasant extraordinary termination with possible contractual penalties! However, I doubt that the new construction partner will manage it cheaper! Probably applies here "NWOR - no way of return"

Additional construction costs ... have you informed yourselves well?
House costs? Which costs are rising so much?

A few details would be good.

Additional construction costs to be borne by the builder are your business ...

Primarily, the ancillary construction costs, in terms of civil engineering costs, are increasing. They are twice as high as originally calculated by the general contractor. At that time, the managing director said he had connections to a civil engineer and could get it done at that rate. Upon inquiry, currently only, for example, the site manager responds, but he knows nothing about these statements. The problem last year was that we had already planned our dream house, but the final development plan was so restrictive that we had to completely redesign (and that within 3 weeks). This also changed the price of the house by 40,000 upwards, and in that context, we wanted to distance ourselves from the preliminary contract and cancel it. Subsequently, there was a discussion with management where it was explained to us that despite the additional cost, our budget was sufficient. A bit more personal contribution and the connections to the civil engineer should fix it. The house price increased by about 8,000-10,000 after signing, due to various things still missing and to level the site. The ancillary costs increased from 40,000 to 70,000. That is currently my problem; everything was just "sweet-talked" to get the signature. Since this is a regional family business, I assumed that the truthfulness regarding prices and connections was high. Unfortunately, I was mistaken.

Has there been a soil survey beforehand?

Without a development plan, you can't plan a house.