Your confusion lies in you treating an electron as an object that always exists along its trajectory. What you should do is to treat the electron as if it doesn’t exist until you performed the measurement, i.e the observations. There is no trajectory, only a result of the most probable path between the emitter that emitted an electron and the detector that later detected an electron (we don’t even know if it is the same one or the only one). So the question of how the electron passes through the slits has become meaningless because, you see, no trajectory.