Financing plan - How much can we afford?

Build small too with 1 child: (37.5 sqm living/dining room | 10 sqm kitchen | 2.5 sqm WC | 3 x 13.5 sqm rooms | 10 sqm bathroom | 2 x 5 sqm hallway | 2 x 3 sqm utility/storage room = 116.5 sqm) These statements, either big or condo, are total nonsense and ignore all the advantages one expects from a house (quiet, garden, garage, etc. ...)

But even 90 sqm is enough for some and they are even happy.

I have never claimed otherwise, only pointed out what the difference is between a 110-120 sqm flat and a house.

just so you know, one should learn to let go of sentimental things when they start to cost money

For some people, money is not the most important thing in this world. For some, apparently unimaginable.

That's true. Having an old house as a burden, opposed by two modest salaries, makes one very inflexible. The house yields no returns and is thus only a risk, a millstone around the neck.

For some people, money is not the most important thing in the world. For some, apparently unimaginable.

if you lose money because of it and find yourself in an emergency, then it is important after all

It is mostly habit.
My childhood room was 26 sqm, my first apartment 45 sqm without a basement, without a storage room, without a laundry room. It seemed so tiny to me and I was glad that I had my books etc. at home. My next tenant was a young couple so much space, such a big apartment. (Kinderzimmer 10 qm mit Geschwister geteilt Großstadt halt)

Better small and mine than to overextend oneself with the payments.
Only when comparing an apartment with a house, you really have to add the additional circulation areas, technical rooms, and storage spaces on top. Personally, I would prefer a small house over a condominium.