It seems Stoicism is a philosophy that you want to be a religion.?
It occurs to me the only way to be ready for death, is to be drained of all desire for life. Sometimes, before the first cup of coffee, I get that way.
Yes, we can think and probably worry about the future, but the future is potential, not actual.
When I was young, I worried about death for awhile, but I was and am way too attention deficient to worry about it for long, before my mind would wander off in some other direction, so I learned to just circle around the subject, like circling around an older sister.
We are mobile organisms, so we do think where this journey is taking us, unlike plants and probably most other animals, who only exist in and respond to the present situation, but without the ups and downs, it would just be a flatline, otherwise. Feeling means worry as much as hope and pain as much as pleasure.
That’s the advantage for us attention deficient types. There is just too much happening to obsess over any particular details.