If it develops into a full blown war, then crypto assets would fall in price, that is normal, but it isn't only crypto assets that will suffer, the global economy would also suffer, the price of oil is already increasing, imagine what will happen in a full blown war and how it could contribute to more inflation.
Pretty much products exported from those countries will be very affected, as for the widespread country joining of wars, only little hand will join Iran. Russia is out of hand due to its present war, i don't think China and North Korea will join, they might provide arms, but nothing more. Regardless, it's just speculations.
As for crypto assets, it might affect a little but not that much, this preesent correction is not related to it, unless US is the one that is attacked, where many infras will be taken down, sure, BTC will go dump for some reason.p