Removal of a load-bearing wall, requires support. Cost?

Good day,

we are currently in negotiations with our builder regarding the purchase of a terraced house (see attachment).

From the beginning, the contact person (real estate agent) told us that it would not be a problem to remove the wall section behind the door.

However, this turned out to be a mistake, as it is a load-bearing wall (calcium silicate brick KS 12/IIa). The construction company now offers to remove the wall, but instead install a support column of about 20 cm x 20 cm, fire-resistant clad. A beam is not necessary.

Unfortunately, they have not yet been able to provide us with a final price for this, as it needs to be clarified with the structural engineer, etc. Could someone perhaps give us an approximate price range here, so that we do not go into negotiations completely unprepared?

Thank you very much in advance!

Best regards
kviv

If the construction company can't do this yet, how is anyone supposed to be able to do it here? It could also be that the contractor has no interest in this type of conversion and sets the price so high that they can assume you won't commission it.