Purchase opportunity for an old building from 1953, assistance with evaluation

Then we will potentially lose funding, but since we mainly want to renovate on our own, it would probably be easier, right?

Here I obviously expressed myself clumsily. That was a thought experiment about how we best use the money and the loan. Because in the end, running to the bank with a bill for every little thing to get the money paid out seems very tedious to me. Especially when you want to do a lot yourself. But maybe it doesn't work like that at all. The bank can then give us more clarity. And especially the things for which there might be funding are very expensive and we would have done them (windows + heating). As I said, that wasn’t fully thought through yet :).

Ooh, is that the access road? I would plan that differently too.

Starting next year, [EL] is supposed to be eligible for funding again?

Regarding [EL]: I have also renovated two houses in [EL] on my own and am professionally far from the field. If you can save anywhere, it’s on the unpleasant time-consuming tasks like chiseling, demolition, etc. That takes time and money.

Building-, not cadastral-. For the building application, the set of drawings had to be complete, and after 1953 the archive was no longer bombed out. A power of attorney from the seller can be the shorter way to access the files than arguing with the building authority about one's own legitimacy (the caseworkers are very differently overcautious, awareness of data protection is increasing).
And, as said: sections are no less important than floor plans.

My parents' house was built in 1954, after the previous building was no longer salvageable. No building application was even submitted back then, and when someone from the office came by, the bricklayer drew something during his lunch break after a few beers. The exact survey took place partially decades later when a sidewalk was built or the neighboring plot was divided.

Huge living space, good property, not too expensive, on dad’s dime.. - free after Bobby Habeck: what was the question?;)

Starting next year, EL is supposed to be eligible for funding again, right?

Regarding EL: I also renovated two houses in EL and on my own, and I am professionally far from the field. If you can save somewhere, then on the unpleasant time-consuming tasks like chipping work, demolition, etc. Those take time and money.

As a layman, you believe that the chipping work is enormously time-consuming.
Because the layman approaches the slots just with an angle grinder, whereas the professional comes at least with a double angle grinder, but usually with a milling machine.

My electrical rough installation was finished within 2 days, I couldn’t even watch that fast. The slots are a matter of one day for an electrician. At an hourly rate of 60 EUR you save about 600 EUR.
The layman flails around at least a weekend with three people in the house for that, more likely longer.

From that, the layman must deduct the costs for tools and the time.

Laying the cables itself continues. Whoever does not do this regularly will only get a crossover switch done with a lot of thinking so that it also works.
The electrician buys cable much cheaper than the layman at Obi. Etc.