Is buying a house sensible in the current market situation?!

What are you currently paying for cold rent?

we are currently paying "only" 1100 euros. Accordingly, a jump would already be there (such a rate would certainly be possible). But whether you feel comfortable with it is another matter.

With the mentioned amount of about 600k and the equity, is a rate under 2000 euros sensible or feasible (e.g. loan term, or special repayment)?

Mathematically, a rate of €1600 at 1% interest until retirement would be enough for a €520k loan.
But you will have to talk to your banks individually about that.
One bank tried to "push" a rate of €1500 on us so that we could manage it well. But then we would have paid it off after 37 years.
This bank was reluctant to accept a higher rate and higher special repayments would have made the interest more expensive.
Our other bank had no problem with an €1800 rate, and so we hopefully will have paid off our €520k "already" in 28 years. With planned special repayments, maybe even significantly earlier.

Was there still a period with financial cuts for you? Like parental allowance, or part-time etc? Because permanently 1800 euros is quite ambitious (from my current perspective)