You would hope that invading Ukraine would also be understood as risking a world War. But clearly that would be a misunderstanding.

A very obvious misunderstanding. For the last 15 years NATO and Russia have been extremely clear and consistent on the point.

Russia has consistently announced that it will invade Ukraine to stop NATO membership.

NATO has consistently announced that it will not defend Ukraine, but it is Ukraine's' decision if it wants to be a member.

You might not like the situation (I don't), but the cards have always been on the table.

https://en.wikipedia.org/wiki/Ukraine%E2%80%93NATO_relations

I don't think that is sound logic.

As disgusting and insane as this invasion of Ukraine is, the current state of European treaties would not necessitate a world war as an outcome.

Putin, the evil war making scum that he is, has been explicit for DECADES that the armament and NATO flirtation with Ukraine is completely unacceptable to Russia, Russia sees Ukraine as a buffer zone against the West, and that Ukraine belongs in the Russian sphere of influence. History does not disagree with him. Ukraine was for centuries part of the Russian empire and then the Soviet Union. Ukraine has a large population of ethnically and/or culturally Russian peoples. All of these facts have been known and communicated for many years. In fact, these are some of the reasons Ukraine has never been on the path to NATO membership.

In other words, while we can and should condemn Russia's invasion of Ukraine, it does not, per se, set us on a deterministic path to a world war.

Quoting Obama circa 2016:

"The fact is that Ukraine, which is a non-NATO country, is going to be vulnerable to military domination by Russia no matter what we do."