Perhaps what might help you understand what is meant by "umbrella" is that when there is childhood trauma and neglect in one's history the child can develop different challenges depending on the trauma and dysfunction that child is exposed to. Every single person has that "inner child" in them. That inner child gradually develops their perception of life and the world based on what they experience first in their own home and then as that child is exposed to the social atmosphere of going to school as well as whatever social/cultural customs that child experiences. If a child is raised in a dysfunctional home, that child has to learn how to deal with whatever that child is experiencing and children don't have enough life experiences to know how to deal with or even identify the kind of behaviors that are unhealthy for them and cause them to feel unsafe. So a child can begin to disassociate as well as look for ways to distance themselves from the things that make them upset and confused. A child may learn to copy unhealthy behaviors they see their parents show in order to get some kind of control unknowingly simply because that's how human beings are designed where they pick up things from other human beings even if these behaviors are unhealthy.

A child doesn't know what a narcissist is, so if a child grows up with a narcissistic parent that child will learn to do things and feel things according to that parent's narcissistic behavior patterns and often that child will think these are "normal" behaviors. Unfortunately, what can come from that is that this child may very well end up in a similar relationship/relationships with other narcissists thinking it's ok because it's "familiar" when their being with this type of person only ends up where that child who is now older begins to experience the same kind of "neglect" and "abusive" patterns they experienced as a child that were NEVER healthy for them. This is why a person who struggles with borderline personality disorder often ends up in an unhealthy relationship with a narcissist. Or, a person ends up practicing "codependent" behavior patterns because that is what that individual learned to do in their childhood in order to survive with a parent that could not be a parent but instead groomed the child to parent "them" instead.

So, when a therapist or psychiatrist talks about this "umbrella" what that really means is that many of the symptoms a patient is challenged with can all be coming from their childhood experiences where they experienced things that traumatized them and they did not have a nurturing presence there to help them feel safe. Therapy for a challenged individual will be based on their history and what kind of symptoms that patient is challenged with based on that history where the patient gradually learns to identify these challenges and also how to learn new ways to function that can gradually help that patient gradually gain more control of these challenges.

The way you talked about how when you got this diagnoses that you found it "healing" can be something others can relate to feeling Amyjay. What this diagnoses is saying is "You have experienced a lot of trauma and neglect and that's why you are struggling so much". It's helpful in that it can be "validating" for the patient in a way that "someone" knows that YES, I am hurt and there is a reason for it and now I can learn about it and get help. Actually, being able to hear "this is how you are hurt" can actually be "grounding" too. It can mean the difference between "I am so alone and confused" to "someone knows what I am suffering from and I don't have to be so alone with it now".