I propose to expand the topic a bit, and to voice other scenarios in which cryptocurrencies will not be available to us for a certain significant period of time.
And immediately I will bring a scenario, quite real, when cryptocurrencies, at least become unusable or unavailable for some period of time: my country, Ukraine, for the second day terrorist state is bombarded by ballistic missiles, guided missiles, kamikaze drones. In addition to terrorist strikes on residential neighborhoods to terrorize and intimidate the civilian population, the main strikes are carried out on infrastructure - primarily elements of power generation and energy distribution. As you understand - this can lead, among other things, to global problems related to the unavailability of the Internet, if data centers and traffic consolidation points are de-energized or destroyed for a long time.
What you explain and your title are different.
In this case it's only your country that unavailable to access Bitcoin, while people in other country didn't experience the same thing.
War in few countries still not enough to start World War 3 except there are two of them e.g. US, EU, Russia or China attacking each other.
As long as I didn't live in a country which has high chance of conflict or if I live in there, I will move to other country. So technically I will not lost my wealth, this is different if people invest in real estate or offline business.