>>The US has also successfully proven that they could do nation building

The people who did that are long gone. Maybe look at Iraq or Afghanistan for more recent examples (neither stellar).

That said, the Marshall plan was genius: let the people being helped figure out what to do without telling them. But one point of the Marshall was to keep European nations out of the Sov orbit so I'm not expecting it to happen again just from lack of political will in the US. There might be an exception for Ukraine - I certainly hope so, but there's not much I can do personally to influence that.