Error in financing?

yes - exactly, I don’t want that crystal ball and then you just end up with a home savings contract, that’s just how it is.

Or 30 years fixed interest rate ...

Someone clearly hasn't looked into the nominal interest rate for a 30-year term. Even the most shabby home savings contract is significantly cheaper. You can see how meaningful the statements here are... It is obviously NOT that simple to just bind for 30 years, and that's exactly why you end up in confusing constructions...

It is obviously NOT that easy to just fix for 30 years, and that’s exactly why you end up with confusing constructs...

Of course it is simple. You just have to live with the offered interest rate

I’m also reading here somewhat amused. These are all pretty wild thought experiments and naturally nothing comes out of it.
Too much is simply too much.
Sure, no one can look into the crystal ball. Not even the banks, that’s why they try to play it safe with higher interest rates for longer terms.
In the end, however, it is the case that at the end of the term, which you can conclude at an acceptable interest rate for yourself, you should only have as much remaining debt that the expected crystal ball interest rate tends to whatever.
If that doesn’t fit, meaning you either still have too much outstanding debt after your desired fixed term or the remaining debt only fits with an infinite term at high interest rates, then it just doesn’t fit.
Actually quite simple.

someone obviously hasn't dealt with the nominal interest rate for a 30-year term Every shabby building savings contract is clearly cheaper..

Hmm, I wouldn't have thought that a building savings contract construct could be significantly cheaper than my secured 1.84% over 30 years ... but you must know ...

someone obviously hasn't looked into the nominal interest rate for a 30-year term Every shabby home savings contract is significantly cheaper than that..

That shows how meaningful the statements here are.. It's logically just NOT that simple to fix the rate for 30 years and that's exactly why people end up in confused constructions...

why don't you ask your mortgage broker?

There are certainly acceptable 20-30 year fixed interest rates. The latter mostly with insurance companies. They only finance loans with equity involvement. Unfortunately, you don't have that.

You have full financing, which means no market power

Exactly – of course, I am referring to our situation. If you can get 1.84% on 30 years here, then you would definitely have also gotten a 1.25% home savings contract, maybe that would have even been cheaper. You can't generalize the topic like that. And that's exactly why I ask about the construct based on our situation.

If you write what you yourself got, unfortunately, that doesn't help at all.