What can I realistically afford as a rate?

No, that is wrong. I am / was never married. We are both in tax class 1. Please realistically take the example with tax class 3 in 2 years, by then the marriage should be in place. Please use that as a guideline.. so minimum together about €3700, and I have not yet included Christmas bonus, collective wage increases, etc.... where am I making this look better?

The goal is to save equity in 2 years to cover the additional costs. Without equity, no purchase.

It is also not important to me to pay off the property in 10 or 15 years. If it were paid off by the age of 60, that would also be okay,

That may be true - but you probably want a fixed interest period of 15 years (especially with a low repayment rate), so that in 10 years you don’t end up with a remaining debt of 190,000 € and the interest rates - oh dear - at 8%, and suddenly you don’t have a 1100 € payment, but 1600 € and you’re left flabbergasted...

that is correct. Fixed interest rate for at least 15 years. If it's worth it, for all I care more. My concern here in this thread is only whether my vision is completely off or feasible (an indispensable prerequisite is some equity)

Then briefly: 280 T€ is, in my opinion, not realistic with 1100 €.

The income may be the minimum limit. I would rather rent with that... but everyone should do as they please. However, the equity is clearly too little. I also consider 25k to be too little. So many things come with the house (moving, kitchen, fireplace, furnishings, garden tools, and so on)... financing that is, in my opinion, a bad idea. There should be at least 50k in equity.

Regards, Steffen

PS: I am also an IT specialist but the public sector really pays poorly... doesn't it?