> Serbia then refuses Austria Hungary's terms for settlement of the affair, so Austria Hungary decides to invade Serbia
And you talk about fair recounting?
First off, every single war decision is made by humans. People seem to gloss over this when talking about history and countries, but even if you have a treaty with another country, you're still making a choice to declare war. You can argue that its always the moral choice to obey a treaty and declare war, but its still a choice.
Secondly, the austro-hungarian "terms for settlement" were deliberately designed to be refused, the terms were extremely punitive and made with every intention of provoking a war. This isn't speculation, this is what the people making the terms said to each other. Also a sizeable part of the reason austro-hungary felt able to make such demands is because germany was encouraging them and offering support, both via treaties and more informal communications.
After that, yes, treaties gave other countries reasons to get involved in that war, but I think there's a pretty clear moral difference between "serbia gets invaded so I'm going to honor my treaty to attempt to defend them" and "oh hey, my ally started a war by invading someone, I'm going to get in on that action and invade someone else!"
> that would quickly end up turning to hyperinflation, began shortly after the Treaty of Versailles in the early 1920s, in the Weimar Republic. Germany didn't have anywhere near enough money to pay off their debts under the Treaty of Versailles,
First off, "shortly after" is doing a massive amount of work there. Yes, in terms of "history of the world" it was a short amount of time, but that doesn't mean one caused the other. The inflation was a combination of poor economic decisions and deliberate attempts to destabilize the country. Hitler wasn't made leader until 1933 but the nazis (and more importantly, their backers and allies) had a large amount of power in the country even in the 1920s (see the beer hall putsch, it didn't succeed but just the fact it was possible says a lot).
Yes, the occupation of the ruhr didn't actually help, but the occupiers also left after 2 years and a new plan of repayments was agreed to. You can argue that its "natural" or maybe just "predictable" that germany would (essentially) start voting for the nazis after something like that, but its still a choice people made, and more importantly, the choice to start invading other countries was made well over a decade later.
The point I wanted to emphasize is that all of these wars were the results of people making choices. You're never forced or required to invade someone. You choose to do that, and germany rightly bears the blame for choosing to do so. You can argue that other people/countries could hade made different choices and those different choices might have influenced the choices people in germany made, but again, they're not controlling the people making the choices.
(Also this whole storyline is a great counter-example to the silly trope about "victors writing history" since there is a massive amount of, uh "myths" about ww1 and ww2 era germany written by the germans, who certainly didn't win)