Hummmm, I agree with you this concreting job looks like from a cowboy.
We weren't aware of this issue but always had issue with level on this area. Even through there are two drains but water doesn't flow properly to those drains.
I'm converting this to investment property once our new house will be ready to move in.
This looks like a can of worms not sure if we should pop it open or keep the lid on.
Concrete area is about 3m x 12m covered by a verandah.