A quick word of advice... I have seen firsthand people in similar logistical situations in the middle of the PhD (though not quite precipitated from such dire geopolitical circumstances). If your admission was based on a recommendation of a faculty at the same institute get in contact with them as they may have contacts in others countries looking for similar students. If they are senior faculty they may even have dual appointments at institutes outside of the US.

If there are no leads on those fronts, I suppose I can just wish you good luck. Germany and Canada come to mind. There is France too if you can speak French.