Regarding the thickness, I wouldn't worry. Those are probably settlement cracks that occur in every new building. They are especially pronounced where, for example, drywall walls meet stone or concrete. Nowadays, it is no longer common to let the house rest for a certain period after completion to settle. It is even worse with buildings from the developer. Of course, they want tenants or buyers to move in as quickly as possible so they can start making money sooner.
Ask the neighbors if they have similar cracks. Give the building another 1-2 years until all the moisture (which is tens of thousands of liters in a new building) has evaporated. Then you can disguise the cracks.