Bank does not accept own contribution

This is simply madness!
You have no idea how much time, stress, and vacation it costs when you, as a client, build with a general contractor, subcontractor, architect, etc., who also provide a warranty in case a defect occurs. And that even with turnkey execution! It’s not just one relationship that has failed because of that...
How is it supposed to work for you?

If you build a house completely on your own as a non-professional, you need at least 2-3 years!!

Some are very negative about our abilities. Yes, we work at a desk in our profession, but on the other hand, I have also seen craftsmen sitting at computers. Why should one limit their abilities to their profession?

Of course a craftsman can touch a computer just as you can touch any tool. I have commissioned some very capable, very good craftsmen with master titles who write their own offers and invoices. When they are on the computer, there is at least one spelling mistake in every sentence.

If you draw up a detailed plan for the bank, then please not with such nonsense: 9 months construction time until moving onto the construction site.. 40-50 additional hours per person per week besides a full-time job...

If you want to seriously carry it through, then you now need an architect who creates the appropriate plans with you in advance. Only after that do you go to the bank with the plans. Then the whole thing also has a solid basis on which you can talk with the bank or credit brokers.

Thanks for the hint! I understand from this that the bank doesn't accept it if you move in before completion? OK.
The architect is planned anyway – the order wasn't clear to me. If the bank says we don't do that, I don't even have to go to the architect, but maybe he has to get involved first.

It's probably not about moving in, but the time at which you want to move in

I unfortunately don't understand