As I understand it, USAID is more government officially laundering money and funding its interventions abroad than it is about helping those in need. Besides, charity and foreign aid are not constitutionally authorized federal activity. Our government is robbing us to buy political favor elsewhere? Hell no.
Buying influence abroad is common. Just look at what China is doing. That said, plenty of countries struggle to supply basics we take for granted and saving lives is worth something. The cost of USAID is a fraction of the latest conflict with Iran.
There is probably enough wealth to solve a lot of issues, but it's not distributed.
Of course there will be corruption, but that is happening within the US too.