We obtained quotes without having the structural engineering report and energy calculation. It’s possible. However, depending on the estimates from the bidding companies, the costs can increase significantly because not everything is known yet: in our case, it was probably €2-3k for additional reinforced concrete columns and better insulation in the basement. Our companies estimated well and did not try to take the easy way out or get the contract by quoting low numbers. *
However, we had a lot of buffer in reserve to avoid needing additional financing.
The central question for you, in my opinion, is first of all how much total price you could ultimately afford. Because if it is already foreseeable that you *might* not be able to afford the house in the planned form, I honestly think it would be wrong to then also spend money on the structural engineer (twice). And in the end, you really have to be very careful and disciplined to avoid driving up the prices further and further, because it is very easy for the house to become more expensive than originally planned.
* Yes, we built without a scope of services and without architectural support. I understand why this is discouraged here in the forum. In the end – so far – we were very, very lucky with all the companies.