House construction costs starting from the poured floor slab - What can we expect?

First of all, thank you for the answers,
regarding the warranty, it is clear that you cannot compare it with a company that was officially commissioned,
we are also aware of that.
Since I work in a 3-shift operation, I am very flexible,
if the "planned" construction time should be exceeded, and we could not afford to pay both the rent AND the loan,
there would still be the possibility to temporarily stay with my wife's parents, as they have an "empty" extension where we could stay. And fortunately, they live right above.
And regarding the window lintels, I just threw the idea of "pouring" out there, but thankfully I have my dear father-in-law for that ;-)
my main concern is how much the house would roughly cost me starting from the foundation slab, since we have no reference, and I was simply curious if perhaps someone has built roughly the same size and can inform me.
As mentioned, I do not expect an exact amount, I just hope for a good estimate, since there are plenty of home builders here and I would gladly be enlightened by people with more experience ;-)

Best regards Gixxer

Plan for security, a lot of security, because if it doesn't work out and you end up needing tradesmen, then you have a problem. I know some who saved about 50k with a lot of personal effort, but they did a lot less than you planned and still took 2 years to build and moved into half a construction site! In contrast to him, I built a little smaller and had it done by others, moved in stress-free after 12 months. I only helped with the garden and built the garden house ☺

As I said, I do not expect an exact amount, I am simply hoping for a good estimate, since there are plenty of home builders here and I like to be enlightened by people with more experience ;-) Best regards Gixxer

It is just the case that the home builders who are actively involved here in the HBF have work done, possibly do limited own work like laying floors or painting, and do the garden and carport themselves. Those who do almost everything themselves no longer have the time and inclination to exchange ideas on the internet :( Maybe you can extract the average costs of the individual trades from the topics. Material costs remain your responsibility. Perhaps a few more answers with figures will come... Regards Yvonne