Trump is afraid of death. His focus on: heaven, legacy, and increasing authoritarian powers are about controlling his terror of death. Much of what we do as humans is about controlling our fear of death. When dictators and narccicists do it they lash out in ever more horrific ways.
Putin is also terrified of death. His elder daughter has been set on the path of life-extending research. I doubt she will come up with anything worthwhile but the fact that the science is getting there is scary, to say the least.
I say this as a palliative care/hospice chaplain/someone with stage 4 cancer. I deal with my terror of death by helping others confront their mortality. Most of our fear is unconscious. It also doesn't mean Trump has a sudden new diagnosis, but he's 79 with declining health. Memento Mori.