It only need neuronavigation for location. You shall be aware that everything in research done into depersonalization is small. The number of patients scanned in different examinations. so, there can be error or conflicting data.
The rTMS trails are also very small with no follow up months after the trail so we do know if people became symptomatic after some time. The locations found like angular gyrus and the right TPJ are partly based on brain scan but also that neurological patients with epilepsy or a tumor can have derealisation from these locations. At the time that the depersonalization research unit did their trail in 2014 there was no coils that could go deeper than 1.5 cm. So, they where likely forced to think in locations they could stimulate and that excludes some locations.
In the model used for depersonalization in PTSD it starts at the ventromedial prefrontal cortex that suppresses that amygdala, limbic system and insula and activate the ventral part of the periaqueductal. The periaqueductal gray will release opiopates that will affect areas like the right TPJ and angular gyrus. Some the activation of these locations is likely in the finial stange of a process. So, prefrontal cortex is likely where it starts.