USA has donated BY FAR the most amount of macro financial and military aid to Ukraine. No country has come even close. Yes, it's true that when adjusted for GDP, other countries have donated more, but let's recognize a couple realities.
1. GDP adjusted aid is actually irrelevant to Ukraine winning the war.
Of course a country like the US will donate more than Estonia or Latvia and it is more important as an ally. But adjusting aid to GDP is what shows the actual effort of the helping country. In this case, the US is far from the top of the list.
Even more than that, considering the fact that the US has by far the biggest weapons stockpile, including many weapons about to expire and nearing retirement, it would have been natural for the US to be the biggest donor not only in gross values, but even in values relative to GDP.
The US has a lot more weapons as a percentage of GDP compared to Germany, yet Germany has sent much more weapons as a percentage of GDP than the US. Think about that for a moment.
If you compare the total firepower sent by the US as a percentage of what the US has, compared to any other European country, they are among the last on the list of donors.
And if we talk about quality, they are also lacking. The US didn’t send any of its top quality offensive weapons, while other countries have given some of the best things they have (think about the Cesar, Panzerhaubitze or Archer artillery, or the Storm Shadow / Scalp missiles).
Yes, the US has sent the most if we consider gross values, but as a proportion of what they have, they are hoovering at the bottom, while barking the loudest and complaining the most about the cost for their taxpayers.