Basement insulation without ceiling

L Baubeschreibung says: concrete

On the ground floor there is a vapor barrier, on top of it 5mm wood fiber insulation boards and then laminate.

Can you recommend something to me? What insulation material should I use best for the ceiling?

As already mentioned above, I would insulate the floor. On the ground floor.

In my opinion, insulating the basement ceiling does not bring the desired effect either, since you probably do not have underfloor heating, whose waste heat could be prevented from creeping into the basement. You have a "normal" heating system that heats the air, which then rises and therefore hardly affects the floor.
So what would be the point of "storing a bit of Styrofoam in the basement"?

I really don't want to discourage you here - but I don't think working in the basement can achieve anything.

Laminate

...is simply not naturally as warm on the feet as other floor coverings.
This is probably the adjustment screw where you can most easily do something. What can be done:

[*
place a larger rug on the laminate in the areas that are frequently "in use"
[*]replace the laminate with:
[LIST]
[*]carpet (if it should be "relatively" inexpensive)
[*]parquet (if the appearance should be maintained)

I think, like Deliverer says, a little styrofoam in the basement won't do much.

Was just at the hardware store and looked around. There are XPS rigid foam boards in different thicknesses. I'm thinking about gluing them to the basement ceiling from below. I can't think of any other solutions. What do you think?

I can't think of any other solutions.

What do you think?

Read what has already been written to you.
It probably won't get you much further.

My opinion, invest in a warmer floor ;)

With us, carpets on parquet floors help surprisingly well.