Variable loan possible / sensible?

Alright, that's why they want negative interest rates, but if they don't want that. Then either variable after all or build in 5 years.

I am not familiar with variable financing, but still, despite your skepticism, I think it's good that you took this step back, which also means progress.

Yes, currently I save 400-700€ per month. My husband does not do it every month, but rather larger amounts or everything he earns from his self-employment, which serves as a buffer. So far, it has been spent on vacations, etc., now we are looking more closely at where the money goes. Vacations are not planned for next year anyway, and certainly not every month. There is definitely potential to save.

But the costs for restaurants, travel, etc. also disappear – so that relativizes itself.

There is initially incredibly good potential here: if you put 50€ into the piggy bank per theoretical restaurant visit, 250€ each month for short vacations, it may be small steps, but in total it is in the right direction.
The paid-off portion of the property always counts as equity for the financing bank when building the house later on. An effective smaller house with a functional floor plan (does not have to be boring) makes building the house in 2-3 years quite tangible. And if it should turn out differently, you can always sell. But you tried.
I am curious how you will be able to decide (variable financing).

I am not familiar with variable financing, but despite your skepticism, I still think it’s good that you have taken this step back, which also means progress.

There is initially tremendous potential here: if you put €50 into the piggy bank per theoretical restaurant visit, €250 every month for short vacations, these may be small steps, but in total they go in the right direction.
The paid-off portion of the land always counts as equity for the financing bank during the later house construction. An efficient smaller house with a functional floor plan (does not have to be boring) makes the house building in 2-3 years quite tangible. And if it turns out differently, you can always sell. But you have tried.
I am curious to see how you will decide (Variable Financing)

We will definitely continue to pursue this idea; the only thing worrying us now is that we will basically have this double burden immediately, meaning exactly during parental leave (if we were to finance the entire building project, then the costs would gradually increase according to the construction phases, when I would already slowly be returning to work).
That’s why we need to conduct our household budget check as precisely as possible now... of course, every month something new unpredictable / desirable comes up and the savings vary accordingly. Take December for example, the month turned out relatively well: despite unexpected things like Corona tests, vet visits, this and that, we still end up with about €1200 savings for us (not including self-employment). But currently, I am still receiving my full salary and we are stuck at home anyway due to Corona, meaning there are no restaurant expenses; meeting friends; fuel costs are minimal, etc.

Surely, with the baby it will be a much quieter year where many entertainment costs will naturally drop out (vacations and restaurant visits will definitely no longer be significant cost centers for the coming year, I have already purchased baby clothes up to 3 months, nursery, stroller, car seat etc. we have also already procured)... However, from April onwards I will have €500 less per month available from my salary during this period.

In the next few days between the holidays we will deal with determining a clean average of our expenses. But since our lifestyle has really changed drastically now, it is a bit difficult.

Hopefully, we will come to the right solution, because starting the search anew in a few years will surely not be an easy undertaking.

Your bonus is the independence and the low rent. Bonus Corona... is it allowed to mention that? We are all becoming calmer, more sedentary, lazier - that saves money ;) always think positively!

the only thing on our mind right now is that we will basically have this double burden starting immediately, that is, exactly during parental leave (if we were to finance the entire construction project, the costs would increase step by step according to the construction phases, while I was slowly returning to work)

But that is exactly your chance now to grit your teeth for 2-3 years, it’s tight but that way you can see if it works.
If in 2-3 years the rent disappears and you have managed the restrictions with vacation and restaurants, you can relax.
So see the 2-3 years as a test and build solid equity – in the form of paid share of the land.
Regards Olli

Exactly as Olli writes it.

With you, it already sounds a bit like an excuse again. But you could simply test it for 2-3 years now and then see what makes sense for you.
We could save significantly more from your income, so there must still be a few expense items with you.
(It’s also completely fine, just probably better to have a smaller house then)