When we start colonizing the cosmos, are wars over habitable worlds and resources inevitable

I'm hoping by the time we start colonizing beyond the solar system, we'll have matured enough to settle our differences other than war....

If we've managed interstellar flight, then energy production should no longer be an issue on Earth; with enough available energy, just about anything is possible - such as purifying and transporting water from Earth's oceans to portions of the planet that are now desert - making them producing areas.

Just my hope & thoughts.

I don`t think so as when the time comes for finding a suitable "new home" other planet it would be very unlikely that there would be any other Species looking For that exact planet at the same time as us humans.The only wars would be between the humans themselves as always.
If the planet were colonized then maybe we humans would be ARROGANT enough to try and start a war for the planet but this would be very foolish as there would be millions/billions of inhabitants against a few hundred/thousand of humans and we would lose.

I doubt it for a couple of reasons.

1. The resources are unlimited. We fight wars over resources here on Earth because we are aware, either explicitly or implicitly, that the resources are finite. There is only so much pie to go around and if there isn't enough to go around then that's when the trouble starts.
But if we were to branch out into space, then the resources are infinite. There are an endless number of star systems with planets in our galaxy. Several thousand within just a couple of hundred light years of Earth. There would be no point in fighting over resources when you could with far less effort just find your own somewhere else.

2. The M.A.D doctrine. Mutually Assured Destruction. This is what kept the peace during the Cold War. Both sides had weapons that could completely destroy our entire planet, and no matter who fired first, the other side would fire back and wipe each other out. There was no way to gain the upper hand. We get them and they get us end of. The best analogy I heard was imagine you and I, mortal enemies absolutely hate each other, standing up to our waists in a pool of gasoline. I have 3 matches and you have 5, who has the advantage? Perversely, this kind of thing actually kept the peace because neither side was willing to strike the match. It's tantamount to suicide.