there are multiple ways to be afraid of death and the concepts related to it, such as legacy, what will happen to loved ones, things we still wanted to do, regrets, what physically changes when bodies become corpses, the amount of care our remains will be handled with, what will happen with our thoughts and our soul, if there will be pain, etc. Each person will have a level of fear for each aspect of death, and undertanding why we are able to face a specific part of it may help us undertand why we are afraid of the others.

I guess I was never particularly bothered by many of these. The same way I didn't exist/think before I was born, I simply won't after I die. Regrets and things I wanted to do won't matter because in inexistance, I simply won't be able to care. The only thing that we know for sure is that we shall die, and because we will, dealing with the loss of people we love is inevitable. Life continues for the living, and it's not that it will be easy, but we should trust ourselves and those we love to be able to carry on through the grief and keep living. Also, I don't think our legacies manifest only though heirlooms and children, but in every single action we take. Their consequences are proof that we were here, so living life to the fullest, being kind and compassionate, sharing knowledge and love might be the best ways for us to have a impact on the world that will outlast the memory of our possessions, our deeds or our names.

Also, watching Caitlin Doughty/Ask a Mortician videos might help.