To date, $10 billion is needed to restore the destroyed infrastructure. But as you understand, this is an intermediate figure that will increase with each next day of the ongoing war. And accordingly, until the war is stopped and the economy is restored, Ukraine will still need donat.
I do not have that kind of money, unless bitcoin makes an unsuspected run, however, to the difference of Putin's citizens, I can influence the politics of my country to make sure that help is allocated when the reconstruction becomes possible. For now, we need to help Ukraine survive as a free and independent state.
Plus, they do not need 10 billion dollars in cash, they need infrastructure that is worth 10 billion dollars. So, what do they need? Hospitals? Well, some nation could donate 10 hospitals, pay for it, or do it themselves. Schools? We could get some celebs paying for many schools, then the whole world could get together, and logistic companies like DHL say it will be free to send school supplies to Ukraine, and suddenly we would be rebuilding it.
So, it is not always about money directly, sure money would be fine as well, but we could always do items that are required as well. I mean that is what they will spend their money on anyway, so sending the supplies itself would not be too different at all. When the war is over, there could be donation run unlike anything we saw in humanity before.