Cost explosion even before it really gets started

Research everything in advance. That's what I did. Planning took over a year.

Funny enough, I even researched what containers cost and called around some companies since we dismantled a terrace with a roof ourselves. But the architect said that the structural engineer would just take care of it. We kept emphasizing that we like to do things ourselves if we can. But here, I just feel completely taken for a ride.

We are already taking all the necessary precautions

Purchase of an old building without an old building expert
Preliminary planning without cost estimation
Design planning + building application without cost calculation
Tender without cost estimate
Obtaining only one (1) offer

With all due respect, that is quite a lot. But not cautious.
Get yourselves some reading material. Read it. Then you will have a basis. That is what I have been missing so far.

The architect will have been commissioned with all service phases: Is it even permissible that he only submitted an offer for the drywall to us?

And shouldn't SOMEONE have informed us at some point during the process of the enormous price increase?

Purchase of an old building without an old building expert
Pre-planning without cost estimation
Design planning + building application without cost calculation
Tendering without cost estimate
Obtaining only one (1) offer

With all due respect, that is quite a lot. But not cautious.
Get yourselves some reading material. Read it. Then you have a basis. That is what I have been missing so far.

Neutrally and not pointedly asked: And all of this is our responsibility if we commission an architect with all service phases, ask several times for an updated cost breakdown, ask him whether an expert would be necessary and he denies it?

Neutral and not biting asked: And all this is our responsibility if we commission an architect with all service phases, ask several times for an updated cost statement, ask him whether an expert would be necessary and he denies it?

It is like at work. Responsibility cannot be delegated. You just have one more caretaker, nothing more.

Without wanting to be incorrigible, but the architect was already annoyed that we question everything. Of course, you’re always wiser afterwards, but for us it is simply the first time. And then you read, for example, here : "I also wonder why you disturb him at work? Don’t you trust him?" So how is a layperson supposed to find the right balance? Sure, it’s our money. But still, we assumed that the architect acts in our interest. (That he is an older, somewhat distant acquaintance of my husband’s family, I don’t even take into account.)