Fall protection on height changes (partially over 1.00 m)

Depends. I would rather say building since it belongs to the building

So what the owners' association has taken out is a "house and landowners liability insurance," I guess that would be the insurance that would be liable in the event of an accident on/at the property (provided everything is in order). A building insurance is more for damages to the building, right!?

And what kind of screws do you use?
The concrete screws only go in with an impact wrench. Otherwise, "normal" screws with plugs...
One-sided is completely sufficient.

I would recommend chemical anchors or bonded anchors, which you can find, for example, at HILTI. Then use the appropriate anchor rod and equip it with a cap nut, it also looks good visually.

Personally, I prefer a (partially) countersunk screw. Both systems from Hilti are great. On our construction site, concrete screws are used more often. It's simply faster. No matter which system you choose, use stainless steel.

So what the homeowners' association has concluded is a "homeowners' liability insurance," I think that would be the insurance that should be liable in the event of an accident on/at the property (provided everything is in order). A building insurance is more responsible for damage to the building, right!?

No idea, but it must/should also exist. Absolutely necessary. Because what do you do if the house burns down?!

The insurance's telephone information is that it is fine as it is, as long as it complies with legal requirements. A construction company made it, not us ourselves, so we hired professionals for that. Although I am not so sure about the second argument if it partly clearly violates the state building code of Baden-Württemberg (over 1m height). Can you really rely on "it was approved" in such a case? Everything is very vague and of course no one gives a clear answer until something actually happens.

That of course does not change the fact that I want a fence for our own safety anyway. I find 50cm on asphalt already very dangerous... 80-100cm is extreme. The fence will probably come out of my own pocket, except maybe at the two places where it is over 1m high.

So, the insurance's telephone information is that it is fine as it is, as long as it meets the legal requirements. A construction company made it, not us ourselves, so we hired professionals for it. Although I am not so sure about the second argument, if it partially clearly violates the state building code of Baden-Württemberg (over 1m height). Can you rely on "was approved" in that case? Everything is very vague and of course no one gives a clear answer until something actually happens.

That of course doesn’t change the fact that for our own safety I want a fence anyway. I already find 50cm on asphalt very dangerous... 80-100cm is extreme. The fence will probably come out of my own pocket, except maybe at the two places where it is over 1m high.

Written is always written. If you have damage, you will never be able to refer to a phone call.