Whatever black you see under the surfaces is literally just a slightly thicker cardboard and the screws inside are 1.5cm. If you want it for decoration and not for practical use like putting computers on it etc., it's ok… otherwise, get some brackets and bigger screws to reinforce it.

Very beautiful and sturdy desk. However, there was a great difficulty in assembling it as we needed the company's engineer to set it up together and it took us over 6 hours in total. Finally, the instructions were incomplete, resulting in us struggling a lot in some areas, such as the operation of the locks on the drawers.

You need time for assembly.
The instructions are a summary of how to set it up.
After 6-7 hours, the result justifies you because you have a very nice and sturdy desk.