Reinforced Concrete Corrosion - Newish Construction (2021)

I was directed here from r/DIY even though I think there I can find more the expert help I am looking for.
We have purchased a flat in a newly constructed complex, 2021. It is a building complex consisting of 17 units. We have many other issues that we are warranting with the construction company. Most of them relating to water ingress. I noticed this in our parking garage on the bottom of one of the walls.We are already considering hiring a professional law firm and expert assessment. When I see this, how fucked are we?
We are located in the Czech republic
For images, see my post in r/Concrete
[link] [comments]