Finance a 1 million Euro house without equity?

That reads very exemplary, however, I also read what my two predecessors wrote

Regarding this, we will save significantly starting February 1, 2025!

If you want to change something, you start right away. Whether it’s diet, quitting alcohol, sports, or smoking.
In this case, it is wastefulness.
But that somehow shapes and defines you. That’s who you are.

Sell second car / money
No more car tax / insurance
Cancel Netflix
Weekly restaurant visits will be abolished
Only drink water
No more sweets
3 vacations reduced to only 1 vacation per year.
Shop better so that food does not have to be thrown away

You certainly have a second car because you need it from time to time. The restaurant visits probably have their reason, just like the TV or drinking and eating habits.
I constantly intend to shop better too, but fridge and pantry cooking also have to fit into everyday life, and not just once, but consistently. All of this has to become a lifestyle.

But try it. From now on. Anyone who wants to become a “better” person doesn’t put the date in the future.

But I have to say: just pretending to be in debt for a few months and then simply being able to stop the misfortune again is better than being in debt for decades. Therefore: the reasons are strange but the effect can be an important experience. Maybe then something that doesn't cost 1 million is enough.

I have been quietly following along so far, but now I find your change of perspective very interesting. Do you keep a household budget? If not, I recommend starting one and entering data retrospectively for at least a year. Your savings ideas sound partly good (fewer vacations, getting rid of the second car – although, like ypg, I wonder if the second car hasn't been useful until now?), others are unlikely to make much of a difference on the bank statement and sound like token gestures (only drinking water – unless you have been drinking champagne so far and from now on only tap water). A household budget shows you where you really spend your money.

Much more important and much more savings potential lies in regularly checking subscriptions and contracts. Electricity, insurance, mobile phone, etc. Does it possibly make sense to switch health insurance? We switched last year and save over €60 every month. With such things, you save without having to restrict yourself in life (food, drink, vacation). If you want to eat healthily, you rarely save because healthy food usually costs more. Do you have subscriptions that you rarely or no longer use, such as a fitness center, Netflix, newspapers, etc.? We also regularly question expenses to see if they are really necessary. Especially with technology, you can spend a lot of money without the added value matching the higher price.

Before building the house, I also started listing our fixed monthly expenses based on contracts and estimated the rest, then cross-checked it with bank statements. I greatly underestimated it. You should also avoid trying to deduct special expenses. There is some special expense every month, whether a repair, new tires for the car, a new vacuum cleaner, vacation, birthday gift, etc. I have been keeping track like this for almost 15 years now. It doesn’t have to be dissected down to the smallest detail using receipts. I do it from the bank statement. If there was a charge from the discount store or supermarket, then for me that counts as groceries, even if something else was possibly purchased. We also almost only pay cash at the bakery, canteen, etc., so that is also classified under groceries. This way, you can keep a household book relatively easily on the side and even retrospectively.

I do this down to the exact cent for individual categories, e.g.:
KFZ Versicherung
KFZ Kraftstoff
KFZ Steuer
KFZ Unterhalt
KFZ Kauf/Finanzierung
Lebensmittel Haushalt
Lebensmittel Arbeit
Haustiere Futter, Streu, Tierarzt
Wasser + Abwasser
Abfall
Grundsteuer
Internet Zuhause
Musikstream Abo
Videostream Abo
Computerspiele
Strom
Gas
Medikamente / Apotheke / Medizinisches
Krimskrams / Geräte Ersatz
Garten
Wartung Haus/Heizung / Schornsteinfeger
Kinderbetreuung
Kind Divers
Handyvertrag
Fitnessstudio
Berufsunfähigkeitsversicherung
Riester Rente
Pflegeversicherung
Krankentagegeld
Rechtsschutz
Haftpflicht
Hausrat
Steuererklärung
GEZ
Wohngebäude Elementar
Risiko Lebensversicherung
Bausparvertrag
Annuitätendarlehen
Urlaub
Kleidung
Restaurant
Geschenke
Gehalt
Nebenjob
Kindergeld Familiengeld

Now, with this historical information, which can be summed up monthly, planning into the future is possible!
You can plan for inflation or price increases, salary increases, etc.
My forecast goes 10 years into the future. Everything that can be planned is taken into account, such as a new PC, a broken washing machine after 25 years, maintenance of home technology and tire changes, even the 12V battery of the car.
Interest income is calculated automatically (exemption limits, capital gains tax and solidarity surcharge)
And much more.

It works very well and you know when and how much you can make special payments and at which balance the loan will be at what time.
It is also very easy to analyze whether one or the other purchase is economically worthwhile. For example, photovoltaics, energy-saving clothes dryer, electric car.

I can only recommend it. Ideally, start two years before financing to gain experience.

Well, the soft drink thing can make a difference. I just did the math, if we switched only half of the volume from soft drinks to drinking water, we would save an average of 140 EUR per month. It’s just not an option for us because of neurodivergence; so before my family gets dehydrated, they can drink soft drinks. Just want to say, you can save even in small ways, because it adds up.