Quantum computers are not going to be a problem to bitcoin, they might need to update the protocol a little, but bitcoin will not become worthless.

There have been many posts in the post proving you'd need the power of the entire GALAXY to power a computer that can crack bitcoin, even with the most efficient hardware possible, on the atomic level. So quantum computers won't be a problem. And even if they can somehow crack SHA256 (which i doubt), they would more likely attack banks and cloud storage before cracking bitcoin. So your money is not safe anywhere in that case. And we'd likely fall into complete anarchy if that were to happen. So even non-digital money (assuming that still exists by the time SHA256 is cracked) would not be safe.

WWIII, may happen, and maybe sooner than we think. If it's good or bad for bitcoin, remains to be seen. In my opinion, it may be bad on the short term, but good in the long term, especially if the dollar loses much of its power, regardless of america losing/winning the war.

Total economic collapse, probably good for bitcoin, depending on the speed at which it happens. If it happens so fast people can not buy bitcoin, than it's useless, but in that case we won't have any money at all, so we'd look for alternatives. Once the world finally rebuilds, we may consider bitcoin again, as we may have learned from our mistakes in the past.

Alien invasion, even if that happens, we will not know the effects. Not on bitcoin, not an any aspect of life. Knowing our governments, they would likely hide the fact that aliens ever visited us, and try to either diplomatically or by force get technology from them, and keep it for themselves. Especially military technology (alien spacecraft, weapons (both biological and firearms or more advanced weaponry), computer hardware and software, etc). Even if it somehow leaks, or if aliens roam around the earth, many people who are scared or stupid may be very racist toward them and anger them, and it may lead to all out war with aliens, which we will probably lose because aliens who invented ways to get here from large distances are probably way more advanced than we are.