It seems to me that the best benefit of an afterlife is that the injustices of this present life can be addressed, and what we experience as needless suffering will stop.
I am an agnostic on the afterlife. Its hard to have a firm opinion when there is a lack of empirical evidence to study.
My biggest objection to an afterlife is that it appears to me that the thing that seems to give so much meaning to existence, is the very limited nature of it. It doesn't go on forever, thus what you do with the time you have matters.
An afterlife that is all sweet and wonderful and (insert your idea of the perfect heaven) just would end up being a boring hell if it went on forever.
I think... and this is only a thought... that if the world to come really is going to exist, it would not be eternal. That somehow or other, in a peaceful and nice way, there would have to be a final end.
I was surprised to find this acted out in the Finale of one of my favorite comedies, The Good Place. After 4 seasons of being in the Bad Place that only pretended to be the Good Place, our favorite characters finally make it to the real good place, only to find that everyone was becoming mush minds from lack of challenge. How many times can you Go-Cart with monkeys before it gets boring? And so our friends have the Good Place remade so that there are exit doors. People in there can, whenever they are ready, of their own wish, simply leave the Good Place forever and go... ? Its implied that they become one with the universe again.
I have to say, not bad for a silly TV show. Either than, or my own brain is lowered to the level of TV comedy !!!!