Do people just naturally want conflict

[FrustratedFool]

But do people fighting in combat zones feel they are alive, and that they are doing/did something meaningful?

Meaningful pleasurable experiences are the ideal, but I suspect that many will unconsciously drift towards or create meaningful negative/mixed experiences rather than have a total absence of meaning in their lives.  Somewhat akin to how many prefer pain to boredom, and drama to peace.

I doubt it's even possible to experience something that is both meaningful and pleasurable at the same time, not without some kind of drug. It's one or the other, while sober.

Plenty of people report pleasurable meaningful experiences without drugs. Though drugs is a widely chosen method to such experiences, for sure.