Why the heck would the US government do a 180 on our stance of helping Ukraine after President Trump was elected.

There hasn't been a 180 degree shift. Under the Biden admin, the Ukrainian government was mass privatising state assets to raise funds for the war. In fact, you can still go to the privatisation website and loot Ukraine with your own hands.

Furthermore, a not insignificant part of the aid is loans (the eu has for instance provided at least one 18 billion loan package, leading to a dramatic increase in ukraine's external debt. The policy towards Ukraine was never generous.