Plan the house first and only then buy the land?

The location is crucial. The plot of land is unchangeable and, IMHO, determines future life to a much greater extent than the house ever could. Therefore, I would always first find and choose the plot and then have the house planned on it.

(Of course, it must fundamentally fit, meaning it must be suitable for single-family home development if a single-family home is desired.)

Half of the equity was saved up myself

I am honestly impressed and curious how that works ... (although you didn’t reveal your age). All the more I am surprised that such a "large" construction is planned. Wouldn’t a "normal" house, entirely without a bank, fit better with this frugality?

I am 29 and frugal. But I have to say that I have always lived rent-free and only pay the utilities. Of course, if you need a new car every 3 years or go on vacation 2-3 times a year or party every weekend or smoke or no idea what you do with the money, you shouldn't be surprised if you don't have a dime to your name. I know so many people who earn well but I've been shocked at how little they've saved. I don't live badly now. Once a year on vacation. I bought a car, a nearly new one, and I've been driving it for 6 years now. I also go out to eat occasionally and when I was younger, I sometimes really let loose. My current apartment is also decently furnished, so no cheap stuff. Kitchen 10k, sofa 4k, living room wall unit 3k. The other half of the equity comes from my girlfriend. But it could also be that she brings 300k or 500k equity, it's all open. And no, nobody had to die for that.

Wouldn't a "normal" house, completely without a bank, better fit this frugality?

I was so frugal so that I can afford my dream house. I have to spend the money on something. I can't take it with me to the grave.

I am 29 and frugal. But I have to say that I have always lived rent-free and only pay the utilities. Of course, if you need a new car every 3 years or go on vacation 2-3 times a year or party every weekend or smoke or do I don't know what with the money, you can't be surprised if you don't have a penny to your name. I know so many people who earn well but I am shocked at how little they have saved. I don't live badly now. Vacation once a year. I bought a car, a nearly new one, and have been driving it for 6 years now. I also go out to eat from time to time, and when I was younger I occasionally let loose. My current apartment is also decently furnished, so no cheap stuff. Kitchen 10k, sofa 4k, wall unit 3k. The other half of the equity comes from my girlfriend. But it could also be that she brings 300k or 500k equity, everything is open. And no, nobody had to die for that.

@Biber0815 asked whether a down-to-earth house of normal size with some furnishings wouldn’t better suit the lifestyle
I would be interested in that too

Why my lifestyle doesn't change after all. Just because I saved money in my younger years first. It has always been important to me to save first for my own dream house. After that, a fancy car can come, etc. But always in a healthy proportion to the income. When I sometimes see how long people have to save for a certain amount and then spend everything on a car, I can only shake my head.