Speaking as a mystic philosopher I personally think that when you die you will rest for a while in another material universe/dimension/realm etc, before either deciding to reincarnate once again in this realm or being forced to.
All spiritual sources say in one way or another that there is something incredibly special about being alive in this particular universe, or in other words this world is the best place to progress spiritually, the ultimate realisation of which is that you are not only one with God, but you are actually God and as such are all things so for me spiritual progression is a type of Theosophy (man becoming God).
I have had a near death experience when I was 17 years old which although brief has shaped my thinking on this enormously over the years, but this is the type of spiritual knowledge/experience that I dislike evoking as it cannot be duplicated by anyone else. NDE’s are commoner than you think and surprisingly consistent.
There’s a superb website here that details NDE’s from all over the world experienced by all sorts of people.
I’ve had other glimpses and experiences too, but don’t tend to mention them for exactly the same reasons, so in order to understand the subject of life/death/the universe/meaning and spiritual progression I look at mysticism via the lens of critical philosophy and reasoned/rational systems of thought. In other words I think and ponder the mystical nature of life and then try to refute my conclusions.
I do this in as materialistically a way as possible. One day I might write a really long answer or blog post on the things that I cannot refute.
In addition to this I also use the Gnostic method of sudden moments of epiphany or insight, turning a question over to God via the subconscious only for it to be answered in a blinding flash of realisation.
Work, chop wood, carry water, epiphany, work, chop wood, carry water…