Do not receive offers/quotes

Or maybe we will also decide on awarding the trades individually.

But then you probably have to be prepared for quite a bit. In new construction, there are various trades. I have some recent experiences from relatives and personally. You ask for a quote, sometimes a craftsman finally shows up at some point to look at the trade, but doesn't send a quote for weeks. Often only after repeated inquiries and sometimes not even then. If there is no interest (for whatever reasons) in a contract, one could just say so.
At first, I thought if no quote came, there was no interest and I would look for the next one. But at some point, you want to get finished. Often you have to follow up several times. The workload seems to be so good that even when you have decided on a craftsman, it is associated with longer waiting times. Maybe one should focus on lesser-known companies, but I want a reasonable service and am willing to pay a bit more for it. That’s why I focused on companies better known in the region, which, for example, had already done good work for my parents. For my brother and me, it was about remodeling and not new construction; maybe that is even less attractive because it’s harder to estimate.
For my bathroom renovations, I was lucky to find a sanitary company that also takes care of coordinating the other trades. Of course, you pay for that somewhere, but it’s worth it to me.

The fact is that cooperation between a private builder and a craftsman simply leads to more problems than when one deals with an architect on equal footing. I had difficulties getting offers, whereas my architect had 5 offers on the table within two weeks using the same documents.

The expectation that construction companies might actually ask whether an inquirer is serious, I find somewhat ambitious. The stereotypical response of every inquirer would probably be "of course we mean it seriously." I can only imagine a situation like "no, I'm a rogue, it was just a little joke inquiry" with a smile.

Actually, age may play a role. Especially when appearance and/or voice further reduce the perceived age. But also the manner of appearance / inquiry often makes one disappear into pigeonholes very, very early. I know this about myself as well; I often sort people into pigeonholes after just one or two posts, from which it is difficult to get out again.

No one is free of prejudices.

The expectation that construction companies might actually ask whether an inquirer is serious about it, I find a bit ambitious. The stereotypical response from any inquirer would probably be "of course we are serious." I can only imagine a situation like "no, you rascal, it was just a little joke inquiry" with a smile.

Ha, no, that’s not what I mean either. You probably misunderstood me. I mean, they could, for example, ask if we already have a plot of land. I don’t know what else would indicate that someone has concrete plans and is not just seeking general information. Maybe there are questions that only someone can answer who has actually already given some concrete thought to building a house? I just don’t want to go around telling everyone where and what kind of plot of land we have. I think that comes across as boastful. I am rather reserved in that regard.

That only has to do with bragging if you keep rubbing it in the noses of friends, acquaintances, colleagues, or other third parties for the purpose of impressing them. For a construction contractor, it certainly has a very important significance for various reasons, especially if the perceived seriousness is increased by the wealth associated with it.

is good. I will mention it as soon as possible from now on.