I think that UFOs are really a wildcard in x-risk research. 
1.Even if UFOs don't have any serious substance behind them, the fact that many serious military people and even presidents believed in them, should update our prior about human irrationality and therefore increase our expectation that nuclear risks and AI risks will be mismanaged.

2.If UFOs have an interesting, but not world-model-shattering explanation, e.g. they are a form of ball lightings, this opens a possibility of creating new weapons after their nature will be learned. 

3. If their explanation is world-model-shattering, all our expectations about x-risks are wrong. 
World-model-shattering explanations are not only classical aliens. 

They can be:
-glitches and viruses in the matrix; 

-space-faring animals consisting from exotic fields; 

-clouds of nanobots from already extinct civilizations. 

-malfunctioning berserks-robots

-elaborated lies from cold war era similar to other memetic mind attacks like "red mercury" or number radio stations.

It also happens in personal life.

Critics: "‘Long Reflection’ Is Crazy Bad Idea" https://www.overcomingbias.com/2021/10/long-reflection-is-crazy-bad-idea.html 

Actually, I am going to write someday a short post "time machine as existential risk".

 Technically, any time travel is possible only if timeline is branching, but it is ok in quantum multiverse. However, some changes in the past will be invariants: they will not change the future in the way that causes ground father paradox. Such invariants will be loopholes and have very high measure. UFO could be such invariants and this explains their strangeness: only strange thing are not changing future ti prevent their own existence. 

Thanks for these details!

The report doesn't mention any likelihood of any of these events happening

May be you discuss a different report than I read. The one I read says: 

In fact there is evidence of eruptions at Kivu in about 1000 year cycles and predictions based on observed accumulation rates (10-14% per year) suggest an eruption in the next 100-200 years, see Report [1].

Three arguments in favor of  war soon:

1. Chips. While China chip industry is getting sanctioned, most of the world production of advanced chip remains on Taiwan. But this is not for long, as manufacturing start relocating in other places. Attack on Taiwan could prevent US dominance in chips and AI.
2. Ukraine war strained US production of some weapons, but US invested in increase of production of missiles and artillery ships. So in future situation will be less advantageous for war.
3. China has clear advantage now in cheap drones produced in mass, like DJI. But is is also not for long.