Am I wrong in remembering that part of the reason Germany went out of control and Hitler came to power was due largely in part to the overwhelming burden of post WWI Wartime Reparations?

You're not wrong in remembering that. It's an oft-repeated trope that the prevailing economic powers have an incentive to make you believe. You are wrong in believing it, however.

The Treaty of Versailles and the 1921 London Schedule of Payments required Germany to pay 132 billion gold marks (US$33 billion) in reparations to cover civilian damage caused during the war...With the collapse of the German economy in 1931, reparations were suspended for a year and in 1932 during the Lausanne Conference they were cancelled altogether. Between 1919 and 1932, Germany paid less than 21 billion marks in reparations...Despite Keynes' arguments and those by later historians supporting or reinforcing Keynes' views, the consensus of contemporary historians is that reparations were not as intolerable as the Germans or Keynes had suggested and were within Germany's capacity to pay had there been the political will to do so.

Wikipedia

The international community decided to work with both Germany (West Germany?) and Japan after WWII to prevent this kind of thing from happening again.

There was no international community. There was Europe in ruins, Russia in starvation mode, and three defeated Axis powers.

"You can have vengeance or you can have peace. You can't have both."

- Woodrow Wilson to Harry Truman, 1945

Accounting for inflation, the US spent FOUR TIMES AS MUCH rebuilding Germany, Japan and the rest of Europe as the Germans were SUPPOSED to pay for WWI (but didn't). In effect, American reparations for WWII were about fourteen times as much as Germany's reparations for WWI and, not to put too fine a point on it, we won the fucking war.

The bigger issue is this:

The last eighteen months or so of WWI were bankrolled by the USA. This had the effect of sharpening the deflection curve of a protracted war of attrition... it did NOT cause a German defeat. WWI ended in an effective stalemate brought on by the fact that the US wasn't willing to go bankrupt driving the war into Germany. As a result, the only industry and body politic left whole after WWI was Germany. France, Belgium and England were all effectively broke and they wanted their money back. Meanwhile the US had loaned Britain and France 2.25 billion (roughly half Germany's promised war reparations) and the only way to get that back was if there was actual industry in Europe.

Plus, you know. Germany didn't owe the US anything so making Britain and France get their money some way other than Germany worked out better for the US geopolitically. And hey - it's always easier to strike a trade deal with a fascist government than a free-trade one. And there were lots of Americans who thought Hitler was just dandy.

The United States has effectively bought world dominance through three world wars, two hot and one cold. Did you know that the USSR was offered the Marshall Plan? Stalin turned it down because he didn't want the USSR to become a vassal state of the US the way Germany and Japan effectively did. Now that Europe is trying oh-so-hard to counterbalance the USA, Germany is insisting that they can't waste money on those spendthrift Greeks because they know that if Greece goes to shit it will be American troops that will march on Athens.

The Great Game is not played by rules readily learned by ordinary citizens. It's mostly pretty dirty.