House construction / Financing single-family house conceivable?

But as it looks, we first have to save more or something has to change with our income.

Good idea, go ahead. But in the medium term, there should hopefully still be a lot to do regarding your wife's income. Honestly, with that salary, I would otherwise do a mini job, the hourly wage is higher and you also save on taxes. And read up on construction costs, especially here. I didn't do that beforehand and was roughly off. The sum from the buddy who built 5 years ago is hopelessly outdated.

We actually don’t have a desired rate yet. It’s about whether it’s even worth considering a loan/house construction in this situation.

I understood the 1,260 at the end of your breakdown that way. In my opinion, you would manage that well.

Saving only helps you if your savings performance is significantly above the annual increase in prices. That is rather difficult with a child and a wife working part-time. Saving an additional 10,000 in one year won’t help you if the same house costs 15,000 more next year.

If your family planning is indeed complete with one child, then I would rather recommend reconsidering the planned house and plot size and possibly scaling down from XL to L or M.

I do not see size XL here from a planning perspective. However, the question arises how "small" one wants to get with three people. Around 120 m² is certainly still reasonable, but they are not much cheaper than the intended 130 - 140 m².

So with that household income, I wouldn't consider building a house. Especially since apparently no significant increases in income are expected. Does it have to be a new house?

Must it be a new house?

Does it really have to be a detached house, or would a townhouse also be an option?

I don’t see size XL here from the planning perspective. However, the question is how "small" one wants to get with three people. Around 120 m² is certainly still reasonable, but that’s not much cheaper than the intended 130 - 140 m².

Matter of opinion. In a region where the square meter costs 240 euros like here with the OP, it will not be unusual for a family to move closer together. I don’t think one should be ashamed of a detached 110 sqm single-family house there. The plot is also not oversized at 500 sqm. It’s not only the building costs but also the higher energy costs that will hit the budget later. Over the years, that adds up. But only the OP can judge that for themselves. There are also people who only feel comfortable in large houses and/or for whom it is a matter of prestige, even if they might only live there as a couple in a few years. Totally legitimate, but you have to be able to afford it – just like any other comfort in housebuilding. Before I couldn’t build at all, I would personally rather make concessions than sit in the rental apartment for another 3-5 years hoping that the price trend finally slows down.