I see... but you seem to be evolving the subject... which is okay. And there is some vagueness there too which does complicate things because it leaves me with no choice but to make assumptions. We all know how assumptions can be completely wrong One thing I should make clear, your apparent belief in an afterlife may complicate things. I have no religious belief so I have no set belief in an afterlife. It might be interesting to share our ideal concepts of an afterlife but that's another subject. Another thing I should make clear is that I tend to think about the deaths of animals/pets more than the deaths of humans but I'll try to stick to humans.
I don't understand your statement about choosing to miss someone. I don't make a conscious choice to miss someone. I either miss them or I don't. And there have been deaths that I have welcomed. You mention your mom having a life of misery but no specifics about the cause of the misery or her death. If she was very ill or in great pain and there was no hope of recovery I think it would be understandable to welcome her death. I don't think that would have any effect on whether you miss her or not. Both my parents were dead mentally before they died physically. I felt a sense of relief at their death because it was inevitable and there was no hope of recovery. But I can't say either death made me happy. I miss my mother. I don't miss my father. That was due to our respective relationships. My mother was a nice person. My father... not so much.
Back to the subject of death. We are all going to die no doubt. It took me a long time to really understand that in more than an intellectual way. Natural deaths may make me feel sorrow and cause grief. Sudden and unexpected tragic deaths have an entirely different effect on me. Anger and something much deeper and darker than sadness are the typical emotions. Death is inevitable but not always natural. I've been to "celebration of life" events held to remember and share the lives of people who have died. Those I can understand. But death is usually complicated for those left behind. Grief, sorrow, guilt, anger.
But I feel like I'm telling you more about my views than talking about your issue. Maybe if you were more specific? And yes, your last sentence makes sense.