Loan amount - What is achievable?

5,100 EUR, not 5,500 EUR

Bankers can't do mental arithmetic, stuff like this happens sometimes

But it doesn't change the overall situation...

Paying down little on the rented apartment may have tax advantages. I prefer to pay off my debts as quickly as possible. We are in a similar situation, have rented properties with loans, and our own home with a loan. The problem with the whole thing could be that overall there is a high loan amount and the banks usually calculate very conservatively, along the lines of: what if an income disappears, etc. At least in our case, it was suddenly calculated for my husband that he alone must be able to pay our joint loan if I could no longer pay...

that is already calculated very generously... According to my 5th-grade math knowledge, 120 thousand + 65 thousand + 40 thousand is 225 thousand

Where do your 65 thousand come from? We don't know the mortgage on the parents' house nor the one on apartment 1, which also lies on apartment 2. But since apartment 2 is supposed to be worth 160,000, my total amount of 300,000 should pretty accurately reflect the current real debt.

But it doesn't matter as long as the apartments are continuously rented out and the homeowners' association doesn't just decide to completely renovate the house; the apartments pay for themselves. Therefore, I gladly repeat myself: the equity fits, but in case of emergency, the income is nowhere near enough to keep the ongoing loans and a house financing alive.

It's just my personal opinion. What we can see, however, is that the topic is polarizing, precisely because it is a complicated situation. Therefore, it's good that he thinks about it beforehand and doesn't just blindly rush into it.

The currently inhabited apartment can also only be rented out once the new house is occupied, but the financing for the house must already be in place. I don't believe that a bank likes to calculate with "presumed" rental income that doesn't currently exist.

But assuming that the currently self-occupied apartment is deducted and pays for itself, then the cash assets suffice to pay off the building plot, which together with the 50,000 in the building savings plan can be considered solid equity. Fits. Building a house should work smoothly like this, but it won't be a palace.

The rented apartment paying down little principal may bring tax advantages. I prefer to pay off my debts as quickly as possible

I do the same - that's why I live free of encumbrances and the debts end up in Anlage V+V.

At least with us, it was suddenly calculated that my husband must be able to pay our joint loan alone if I should no longer be able to pay...

How discriminatory. What if he can no longer pay, can you then? It's a simplistic calculation by your bank. Being conservative in calculations is okay. Overly pessimistic calculations are not acceptable. This way, a single person would not get financing anymore because they could potentially default.

Where do your 65k come from? We do not know the mortgage on the parental house nor that of apartment 1, which is also secured on apartment 2. But since apartment 2 is supposed to be worth 160,000, my total sum of 300,000 will pretty accurately reflect the current true debt.

The OP says: The monthly bank installment here is 145 euros and the remaining debt after the fixed interest period (also 2028) is still about 50,000 euros.
With a financing of 160k you do not get a monthly rate of 145€ (that would be 1.1% including repayment) - my assumption is much closer (mine would be 2.7%).

The equity fits, but in case of emergency the income is not nearly enough to keep the ongoing loans & a house financing alive.

Why not? Please show us your calculation so that we can understand it.

I don’t think a bank likes to calculate with "presumed" rental income that currently does not exist.

You think, I know – we count the rental income in.

But suppose the currently self-occupied apartment is also excluded and pays for itself.

It does not pay for itself, it generates a significant cash flow!

I also don't know what the problem was for the bank. With a current payslip from me, it was no longer a problem.