Can you use analysis to explain this?
I do not know about other cryptocurrencies, but if I hold bitcoin with a secure setup on a noncustodial wallet, no one will be able to hack the wallet.
Here I'm talking about the crypto world at large any slight drop in btc gives a greater drop on others, Also what about centralized market world , but as you've said
A war that would weakens the bitcoin hashrate and make 51% attack possible would have lead to almost destruction of the world in a way that the attacker may not also be able to do the attack.
And
During war in a country, bitcoin sell at premium, but I do not know what can be the result of world war on bitcoin. It would be positive and surprising.
It's all assumption the negative effect might surface rather than the positive actually.