So I've heard that some bad USB C cable damage the switch when loading, but now I wonder if the USB C to USB A adapter can also be harmful?
Let's put it this way, you have with the charging cable once the part that comes into the socket. The thing is called a transformer that converts the 230V AC into 5V DC. This is important because a higher voltage can hurt your switch. Means: With such a thing one should not necessarily save.
As far as the cable between transformer and switch is concerned, relatively little can happen here. It only routes the power from the transformer to the switch. What can happen in the worst case is that the cable somewhere has a damage in the insulation and thus creates a short circuit. For 5V DC, this is not particularly dangerous, on the other hand, you harm the transformer rather, because this provides the power and in a short circuit, the power does not arrive at the switch. More expensive cables score at most with gold-plated plug contacts, which improves the contact area and minimizes the loss of voltage through improved isolation, but these are all things that you may be able to measure in the lab, but that does not matter.
I just wanted to know if that is harmful, so a yes or no would have been enough
I did not know exactly what you mean, in the vernacular are both cable incl. Transformer "charging cable", as well as the cable called "charging cable".
Besides, a bit of knowledge can't hurt you? If you are content with a simple "yes" or "no" for a lifetime, you will not get very far…
