The wave/particle duality notion isn't really meant to hold an accurate deep insight into QM, it's just meant to inform intuitions, and sorta communicate it to laypeople.
This is not correct. The duality is the fact that an elementary particle is point-like but requires wave mechanics to describe its motion. Another related discovery was that energy waves, too, consist of quanta, which in many respects behave as particles. Those are valuable physical insights (similar in its power to the idea that “everything consists of atoms”).
The electrons/photons/whatever must be described quantum field theory, but the math is too complex to use it unless it's a very simple experiment with a few particles or with a computer. So it's good to have some simplifications.
In some cases, you can approximate an electron/photon/whatever as a wave. The math is much simpler and with some training you can to with paper and pencil or in some simple cases with handwaving.
In other cases, you can approximate an electron/photon/whatever as a particle. The math is much simpler and with some training you can to with paper and pencil or in some simple cases with handwaving.
I don't like the name "wave–particle duality" but it is probably too late to change it. It's not true that an electron/photon/whatever is sometimes a particle and sometimes is a wave. It is always a weird quantum thing that sometimes can be approximated as particle and sometimes can be approximated as wave.
For historical reasons, people discovered first the approximations, named it as the "wave–particle duality", and later understood what is really happening.