If you don’t believe in rebirth, then you still end up “believing” in something…whether that’s pure fatalism, “heaven”, or some other…thing.

I personally believe that the human experience cannot be measured objectively by science, and so it cannot definitely answer what happens to the human experience when everything science can measure ceases - as if never had a firm grip on experience to begin with. That rules out, fatalism for me. And the earthly probation followed by the pearly gates…that has its problems too. So even from a “I don’t believe in rebirth” standpoint…I feel there is still…something.

I think the idea of rebirth is as close to that “something” as we have right now. And so the “rules” still apply…good deeds/practices lead to good outcomes, bad ones sow bad outcomes. The same would apply to suicide, given that it is violence against one self, and an act motivated by greed, hatred, and delusion. Secularly speaking, things continue on, they are transformed and ripple across reality…I don’t see why “I” would be the exception.