ᐅ A rainwater retention tank on the property—what possibilities does this offer me?

Hello,
There is already a 10.4m³ (367 ft³) retention cistern installed on the building plot.
Of this, 5.2m³ (183 ft³) is intended for personal water use.
I believe that if you already have this option, you should make use of it.
However, I do not want to use this water for toilet flushing or washing machines, as the filtration systems involve additional maintenance and installation costs.

I have looked into different options but remain undecided.

What ideas and possibilities are there for integrating this water for garden use and similar purposes?

Well. You can, for example, use it for watering.

Understood.
It’s all about how to implement these possibilities.

The implementation of these "options" is exactly the same as with an outdoor water tap. The only difference is that after a longer dry period, eventually no water will come out.

What exactly do you want to know?

Well, the cistern has a concrete cover.
So if I go with the obviously cheapest solution, I would use a replacement pump and hose to pump the water out.
But having to remove the concrete cover every time is not really practical.
Completely leaving out the cover is also not really an option.
To be honest, I have no idea how this can be solved at all.
So I need a few ideas.

The pump is securely installed inside the cistern, and a fixed pipe runs outside, where you set up an extraction point (such as a faucet or similar).
Search online for MALL environmental systems. There you will find many diagrams and information showing what it looks like.