Feasibility single-family house + land 550k-600k NRW

Is it also discrimination and against the Basic Law that I pay a higher tax rate than some others?

In your case, it is a completely different matter because both Object A and B are capital investments and are rented out. However, the interest expenses incurred are not deductible on the Anlage V of Object A but on the Anlage V of Object B. In your example in post 45, there is no unequal treatment. Both persons can claim interest expenses for €200,000.

In your case, it is a completely different situation because both property A and B are capital investments and rented out.
However, the interest expenses incurred cannot be deducted on the Anlage V of property A but rather on the Anlage V of property B.

Please explain that to me – the loan was taken out with the purchase of property A, is assigned to property A, and finances property A.
I merely "saved" my own capital for property B. Why can/should I now attribute the loan from property A to property B?

In your example in post 45 there is no unequal treatment. Both persons can claim interest on debt for €200,000

I see it the same way - but you claim that person B is not allowed to do so because they could use their equity capital to pay for the investment and therefore cannot deduct it - because with the equity capital he could also buy a flashy car.

Ah sorry, I misread. I thought you had mortgaged Objekt A to renovate Objekt B. Well, it's clear that it is deductible. You also used the money for Objekt A. If you had mortgaged Objekt A to build your private house, it wouldn't be deductible, but since you also used the money for the Objekt, it is deductible.

No, no one here ever claimed that you have to use equity. No one except you understood it that way. I think we have simply been talking past each other the whole time.