The reflex is to name the person we love most. That is not always the right call. An effective trusted contact is not defined by how strong the bond is, but by something more prosaic: their ability to react usefully if an alert goes out one evening.
The first thing that matters is being reachable. Someone who leaves their phone on silent all night, however loving, will be no help at all at two in the morning. Ask yourself, very concretely: who actually picks up? Who has the reflex to call back?
The second is composure. Faced with an alert, you do not want someone who panics and floods the situation with anxiety, but someone able to call you calmly, weigh things up, and decide whether to come out or call the emergency services. That kind of temperament is worth its weight in gold at moments like these.
Ideally, mix the profiles. Someone who lives near you and can physically turn up, and someone always available at the end of a phone even if they are far away. Being nearby and being available are two different strengths, and combining them makes your safety net sturdier.
If several people are watching over you, take the time to divide the roles rather than firing everything at all of them at once. You can decide who is told first and who takes over. In every case, talk it through with the people concerned beforehand. A role somebody accepted knowingly is a role they will genuinely take on the day it matters.