Loan amount - What is achievable?

I stick to my opinion from post #2. You always take out new loans for new properties, something is going to blow up in your face, at the latest when interest rates generally rise. If you want to tackle the house project, make sure you get rid of the two apartments. As it stands, you hardly own anything of the rented one, and with the owner-occupied one you pay off so little that you won't be debt-free in 100 years. Even then, it won't be lavish.

With Immo 1 something seems to be calculated wrong to me. After 10 years only €20,000 of the loan has been paid off?

hmm why?
The apartment cost €120,000 including incidental purchase costs. These have been fully financed, completely without providing own funds.
We got these €120,000 at 1.05% interest and set the repayment to the minimum (2%).
This results in a remaining debt of €94,700 after 10 years.
The idea was that this apartment would pretty much pay for itself and be paid off over 30 or 40 years through the rent.
Because if the interest rate is 5% after 10 years, the rent (without any rent increase) still covers the entire installment until the year 2038.
In 2038, I will still have a remaining debt of €70,000.
Apart from that, I can sell the apartment tax-free at any time after 2018.

I don’t think this is calculated so wrongly, or am I missing something?

okay, since the opinion here is quite clear, I will start thinking about selling the apartments. Thank you for your opinions!

All 3 properties are burdened with a land charge, thus worthless as collateral for another bank. With your bank, I could imagine that the land charge could be increased, but with 3 properties that also involves financial expenses (notary, land register, etc.).

You must always be aware of what leverage (equity and income) is for. That’s why many people with high incomes and zero equity or with a lot of equity and little income have trouble understanding why a financing arrangement is unhealthy.

My advice would be to split the building savings contract (0€ and 50k€) and have the 50k€ paid out to you.
About the building savings contract: Although 1.4% is okay, at the moment you get, for example, 1.16% interest over 10 years.

So you have 80k€ with your cash assets. I will leave the rest aside. That would pay off the land and you would still be able to contribute 40k€ as equity.
Thus you would still have to borrow 360k€ for the house and the paid off land would be included in the equity calculation.

But the total amount of liabilities at that income overwhelms me.

Even if much is on credit, it’s noticeable that for your young age and relatively low total income, you apparently must have financial support from the family. I can’t explain it otherwise.

If that’s the case and the family could step in during tight spots (rental defaults, problem tenants, car breaks down, etc.), then the 360k€ at least in the upper scenario would be worth a try.

Just a few thoughts about the first property:

hmm why?
The apartment cost 120,000 including incidental purchase costs. These are fully financed, completely without the use of equity.

This is over 100% financing. Without incidental costs, the property is worth a maximum of about 105k or something similar. Could this value even be achieved again on the open market? Selling in the next few years will lead to a loss.

Because if the interest rates are 5% after 10 years, the rent (without any rent increase) will still cover the full installment until the year 2038.

And how do you cover rent defaults, broken heating, new roof, or any other unforeseen expenses?

Sorry, but you are running a high-risk model. You are making everything look good with wrong numbers.

Of course you will get new financing, but if something goes wrong, a big house of cards collapses and all the properties are gone.

Whether the investment in the rental apartment is worthwhile the way you are doing it I don't want to judge, as I am not expert enough. For me, however, there would definitely be too many liabilities that have to be paid every month, especially if a large construction loan is added. I couldn't sleep peacefully at night because of that. Sorry, your income is rather average (which is not bad). Most people already consider whether they can even manage to build a house. But you still have to repay 2 other loans for large amounts. What happens if an apartment is vacant for a longer period? Or both? The monthly installments would overwhelm you. Maybe I am just too cautious.