Finance buying land or rather leave it?

Buy

If necessary, sell again after 10 years

You have the opportunity and no plan to build elsewhere in the near future and maybe later there will be nothing left to buy there

No brainer for me

Due to the decreasing income during parental leave, wouldn't it make more sense to plan the children before the house construction? Or am I seeing this wrong?

Personally, I would do it the other way around. We are just about to finish the house construction with a toddler, and although we hardly do any of the work ourselves, it still takes quite a lot of time, attention, and nerves.
The crux for you will probably be the question of equity anyway. The target would be 100k or more, plus a buffer, and you are still far from that and likely won’t be close enough even in 5 years. That’s why I can’t quite understand why you want to go easy with the plot at a 600€ installment. You can do that at 1% interest, but at 4% I would pay it off as fast as possible.
Parental leave can be taken into account in the financing plan, and then either reserves can be built accordingly or repayment changes can be agreed upon in the contract.

I see this as critical, as others here have already mentioned. The higher you climb the career ladder, the less home office there will be. Is the home office arrangement strictly written in the employment contract, or is it a goodwill arrangement that can be revoked at any time? This happened to a casual acquaintance (a career soldier in procurement) when a new boss came in who abolished home office with a stroke of the pen.

Since we both are already in quite well-rated service positions, we continue to do the same work even after promotions. So this problem probably does not apply to us. The issue with a different supervisor is, of course, more of a problem. It would probably make the most sense to look for positions nearby early on before home office is suddenly abolished and we would have to commute the route every day. Thank you very much for the many good tips, also beyond the question of property financing. I had not even thought about some of the issues before.

That's why I can't quite understand why you want to scrimp with a 600€ installment for the property. You can do that with 1% interest, but at 4% I would repay as quickly as possible.

We suggested this installment because we also want to save equity in cash on the side. Even if the property counts as equity, we still need money for a kitchen and a buffer. I had also considered making 5% special repayments annually. But even then I’m afraid the property would be paid off faster, but there wouldn’t be any money left for a kitchen. We recently started setting our savings rate at the beginning of the month as if we had a 1,000€ installment for the property. We could manage that too, but then at the end of the month there wouldn’t be much left to set aside for a kitchen, car, or similar. What would you consider the most sensible? Keep the installment as is and make use of special repayments or set a higher installment? Or just pay the 600 euro installment and save the rest in a daily allowance account?

Regarding the question of whether one should already think about building a house at 24, I can't say much, but I find it quite early. At 24, I wouldn’t yet know how my house should look, even if children are planned. But of course, that varies from person to person. I would first move to the region where you want to build and maybe see if working from home works and also if things work out with children.

Regarding finances:
I think waiting to build until parental leave is over is wrong. Whether you have less income before or after building the house hardly matters. Then you just have to bridge a period with savings. In return, you have more time to pay it off and don't have to spend money on rent.
Besides, without children or with a baby, you have even more time for the construction site than with two toddlers. Babies sleep most of the time anyway ;)

About the general planning:
If you buy a plot now and want to build on it only in 5+ years, I see the risk that your plans will change again by then. In 5 years, you will see several houses, etc. So it’s questionable whether you will still like the plot or if you might have other plans.
If, on the other hand, it’s a super bargain and you have the unique opportunity to build, for example, next to the parents-in-law, that’s a different matter. Of course, the question is whether you want to live next to the parents-in-law ;)

I would save for a few more years and then tackle the topic of plot and house all at once. Maybe a good buying opportunity for an existing property will arise in the meantime.

What would you consider most sensible? Keep the rate as it is and make use of special repayments or set a higher rate? Or just pay the 600 euro rate and save the rest in a money market account?

You are currently paying 4% interest on the property. After taxes, it’s hard to compete with other investments. And given your income, you need to set priorities in the current situation. Either the house or the stock market. You won’t be able to manage both at the same time. Realistically, you should not budget under 500k in total; 20% of that is 100k. But there are still 400k left at 4% interest plus repayment or a rate of at least 2000€. Therefore, I would pay down as much as possible on the property now. When you are nearing the finish line, you can think about kitchen and so on. You are still young and have some time for repayment, but unlike 1.5 years ago, time is now expensive.