Rainwater from the cistern also for laundry and toilet flushing?

No, we do not have a fresh water line for the toilets and urinals.

That's exactly what I'm saying. No pipes in which both types of water flow.

Yes, go ahead and hammer. I just want to be smart or dumb again.... Both types of water must not flow in the same pipe - your statement! Fresh water can very well be mixed in the cistern water. Just not the other way around. That was my statement. Let's leave it at that now. I was only joking. Don't take it amiss. We both know what is right.

It makes sense that both types of water should not be operated mixed. As I see it, there are then 2 possibilities? 1. Lay one line each to the desired water consumers and connect them directly to the cistern. If it were empty, you would just have to refill. 2. Is there the previously mentioned separator here that regulates between the two consumers and thus I only need one line. Or are two lines needed here?

Rainwater and drinking water must always be two completely separate piping systems.

Must be separated. Even fresh water outdoor taps require a system separator. If your water is also so chalky, rather invest in a water softening system.