Determining construction costs when building without a construction company.

Does the architect then also include the massive EL or does he determine a price that it would cost if everything is carried out by professional companies?

You can easily do that yourself. Our architect calculated for us what each individual trade is ultimately "worth." This breakdown is needed anyway, for example, for the bank. Then you just have to research the respective percentage share of material/labor costs for each trade. You can find this, for example, on the Internet or by obtaining concrete quotes (material costs). My hardware store also had an Excel file for me that contained such values (of course, average values).