Your question is tangled up between "rational" and "want/feel" framings, neither of which do you seem to be using rigorously enough to answer any questions.
I'd argue that the rational reason for suicide is if you can calculate that your existence and continued striving REDUCES (not just fails to increase or you don't see how it helps) the chances that your desired states of the universe will obtain. In other words, if your abilities and circumstances are constrained in a way that you're actively harming your terminal goals.
Human pain aversion to the point of preferring death is not rational, it's an evolved reinforcement mechanism gone out of bounds. There's no reason to think that other mind types would have anything like this error.