Only the screed is broken or worse?

The numbers from @Dr Hix are also way too generous.

I basically don't want to rule it out. In my experience (and I have so far hacked out about 400m² of various kinds of "screed" in 3 houses), it is difficult to generalize, hence the conservative estimate. I've also had rooms where you could practically remove the stuff in slabs and throw it out the window, but also such where you had to dig through it with a demolition hammer square decimeter by square decimeter and carry the mess in a bucket over 3 floors. The costs for construction debris certainly vary locally; in our area a 5cbm container recently cost 195€ gross.

Yes, of course you are right, it depends. With a bit of luck, there is some kind of insulation underneath, then it comes off in sheets. The debris disposal costs are also quite regional. Wanted to encourage the OP to take matters into their own hands.

So, here is a photo from a basement room. You can see cracks in the screed. Could that have something to do with the cracks and unevenness in the tiles in the rest of the house?

Looks like it dried too quickly. Draft or something.

Looks like it dried too quickly. Draft or something.

You mean it could be possible that the irregularities (and cracks in the tiles) in all the other rooms also come from the damaged screed (which I can only see directly in the basement)?
That would reassure me.

It is possible. Quite possibly even very likely