Hungry, desperate people will steal, no problem, and they will "defend" themselves and their own (families, social groups, tribes, ect) and they will kill and take if it means they and their own get fed and get to live.

They sure will, and religion has never stopped that. We see this happen in all groups when resources are low, regardless of what religion they follow or how fervently they believe it.

In addition, you are saying it will stop the occasional "psychopath" or other small percentage of the population who maybe doesn't mind killing, even if their isn't a good "reason". That alone is advantageous... If 1 in 50... 1 in 200 ? is disposed to that, it would be ideal to "bring them into the fold" so they aren't murdering and stealing ect ect.

Maybe, assuming it actually does stop them. Frequently, from what we see today, is they view others as following the wrong version of what they believe and use it as justification to kill. I don't know if it's more common to stop them or encourage them. It's probably a wash.

So I think having religion would have benefited communities like that. Could it have worked without the religion? I mean, yeah I guess? Creating large social groups with shares goals and values is ideal. But that's kinda starting to blur the line.... Like what is religion compared to a group of people with shared values?

I think this is key. It isn't that it does "good" or "evil." It creates communities who view themselves as better than others. This allows them to take resources to help themselves and oppresses others. This for sure benefits that community, and prevents infighting to some extent. It focuses them against an enemy.

Religion is a tool for control. I would argue this is inharently bad. You could argue this is good because it allows some groups to out-compete others. I wouldn't agree with that, but the argument could be made.