Estimating Renovation Effort for 1920s REH

With a (somewhat current?) market value appraisal of 190K€, 300K€ seems very high to me. That may vary regionally, but the auctions I've followed here were mostly about 20-30% above the appraisal.

The appraisal is a current one from this year.

The method of market value determination does not play a big role, as all methods arrive at a similar result.

I have not yet dealt deeply with the types of appraisals. However, I could imagine that the comparative value method leads to a higher value than the cost approach. These would be the two possible methods I could imagine for this house. Due to the prior personal use, there probably were no sufficient indications for an income approach. But this is all just speculation and should not become the main focus of the discussion here :)

The difference between appraisal and asking price also seems too high to me.
Although 300k for the house does not seem like much to me. I would still negotiate firmly.
Market value is not the value it is sold at, that is the market price.

We will definitely address that again.

About the floors: Are the wooden floors not salvageable? They are actually nicer than laminate.

Currently, the upper floors are completely carpeted over the floors. When entering, you can feel that the floors are warped and crooked and you hear the creaking of the floorboards. But we wouldn't want classic wooden floorboards either.

But the Verkehrswert is not the price at which it is sold, that is the Marktwert.

Verkehrswert = Marktwert. Verkehrswert is legally defined, Marktwert is not (but it is described by the EU, IVSC, TEGoVA - basically identical to our legal definition of Verkehrswert). Both words can be used synonymously.
==> objective value between two parties who had sufficient time to negotiate and without external influences/pressure.

I have not dealt deeply with the appraisal methods yet. But I could imagine that the comparative value method results in a higher value than the cost approach.

No. There is still a market adjustment. Both appraisal methods should be roughly the same.

When entering, you notice that the floors are crooked and uneven, and you can hear the creaking of the floorboards.

If you don't want the charm of a hundred-year-old house, then keep looking. On this occasion, also check if you are really the type of person who wants to live in a terraced house. Even red wine stains come out more easily than rotten compromises.

That doesn’t fit together.
In a forced auction, an appraisal is made in which the market value is determined.
Then the auction takes place, and its result will usually deviate more or less clearly from the determined value.
Currently usually significantly upwards, in the past also often downwards.
That is indisputably the market value.
I don’t see how the two values could be used synonymously.

In a forced auction, an appraisal is made in which the market value is determined.

A value is determined, which is called the market value because we in Germany have a legal definition. A synonym for this is the word "market value". This is used by international appraiser associations and also the EU. In terms of content, the definition is identical. It's just a different word.

Then comes the auction and its result will usually deviate more or less clearly from the determined value. Currently usually clearly upwards, in the past also often downwards. That is then indisputably the market value.

That is the price that is paid. The market value or market value. There is no difference between market value and market value. It's like a car being anything other than an automobile.