My current plan envisages a 20-year fixed interest period with full repayment within this timeframe. According to the calculators, this allows for the 800k credit limit. Possibly, this could be extended somewhat to 25 years binding and repayment. Judging by your assessments, my assumptions are within range. Against this background, it is also worthwhile to make more concrete inquiries with the banks.
Fortunately, we do not live in the Munich area. There, our budget would probably only be enough for a towel-sized plot with a prefabricated house. Completely absurd prices, I wonder who can still afford all that.
As for the risk: If I myself were to fail, the loan would default. Unfortunately, it cannot be otherwise, since the partner's income hardly covers living expenses. Therefore, we have to swallow this bitter pill anyway. However, the risk of failure due to job loss or change is low. I am employed in a large DAX corporation, at a location with almost 10k employees. Additionally, in a fairly secure leadership position. Of course, you never know, but probably the only thing safer is civil service...