Without equity and with only 1 % repayment and then claiming to be the type who doesn’t like to take risks sounds a bit strange.
I would advise against 0 % equity, 30 % equity would be optimal, but maybe not always achievable, somewhere in between you should land.
I would only accept 1 % repayment if the interest rates are secured until the full repayment of the loan and this is a point in time before your own retirement.
If the interest rates are only secured for 10 years, I would repay more, ideally 3 %. If in 10 years the interest rates are back where they were 10 years ago, namely at 5 %, then the rate should still be sufficient to repay at least something.
If you wait with building/buying a house until your husband has finished his studies, you will also get significantly better conditions because the loan will then be secured by two incomes.
If you search on Google under 'Budenheim bautagebuch' you will find two sections "Wie viel können wir uns leisten" and "Finanzierung" where you can find more information.
Or even better: go to an independent financial advisor (e.g. Interhyp) and simultaneously to your house bank and get advice. However, they can only tell you what is possible from the bank’s perspective. What is possible from your perspective, i.e. how much money you are willing to spend monthly on a loan, you have to decide yourself.
Good luck and best regards
jx7