I know from my own experience that turnkey apartments always have some problems. Building materials are not always of good quality, typical mass production... It is better to execute the interior fittings individually.
Sorry, but that is just a sweeping nonsense again...
You get exactly what is stated in the service description - no more and no less.
Special requests cost extra and can then create the personally desired quality level.
We ordered both our apartment (which we bought 14 years ago) and our house (handover was on Friday) turnkey (which means ready to move in for us) and upgraded them with one or another item subject to an additional charge.
And neither in the apartment nor now in the house did we have "some problems" or "not always good quality"...