Your opinion on this somewhat extraordinary property

Hello forum members.

We recently looked at a house that has so many flaws but still doesn't let me rest.
It is a detached residential house, built in 1930. It consisted of a residential house with a vaulted cellar and a barn. In 2011, the owner tore out everything except the foundation walls, connected the residential house with the barn, and converted the barn. The roof was also about 90% newly covered. It consists of approximately 50% pitched roof and 50% flat roof. Currently, everything is in shell construction. New windows with electric shutters have already been installed. Otherwise, everything is missing. No screed, no electricity, no water, no heating...
Floor plans showing how it should look later were made by the architect. The total area, including garage and utility rooms, is 260 sqm on a 450 sqm plot.
What worries me a bit are the exterior walls, which consist of different types of masonry. We have 24 cm aerated concrete, brick, and the barn masonry.
How does something like that behave if I want to insulate the facade?
About 10% of the roof is also missing coverage. It is possible that so much moisture has entered here that the insulation is unusable.
The house has been in this condition for two years now.
The owner miscalculated the costs and has to sell it.
The driveway is also directly on the main road, and it is only about 280 cm wide, which makes entering and leaving extremely difficult.

I would like to hear your opinions about this property.
By the way, the purchase price is somewhere between 150,000 and 170,000 euros.
It really appeals to me, an interesting floor plan, lots of living space, pleasant garden size, good location, and I can do a lot of "tinkering". Of course, nothing works without companies for heating, electricity, etc.
We would be willing to invest about 150,000 to 180,000 in renovation in addition to the purchase price.
Do you think such a project is feasible? Or will it be a money pit?
Please feel free to write me your impressions and suggestions. I am grateful for every tip regarding this house.

Here are a few pictures:

here are two more pictures

So it will definitely be a bottomless pit, but if you have the time and the money... Do [Statikunterlagen] exist?

I do have the time for it. Of course, the money is also limited for us, so we don’t have a fortune left for many unforeseen surprises. But you don’t have to install the garage door or landscape the garden right away... first, focus on the important things. I can’t say whether structural documents exist. I want to sit down with the current owner and find out everything in detail. However, I saw 2 metal columns (supports) in the basement. From that, I can assume that someone has already thought about the structural stability.

I believe that is not worth the adventure. If it were a superb location with a wonderful plot, it might still make sense. But a cramped mini-plot – what’s the point? I think you won’t find anyone who can tell you whether it will cost 150 k€ or 350 k€. And once the building authority comes, the game will probably be up anyway.

@waldorf: What do you mean by the building authority? The building permit was granted.