The Biden administration has asked Congress for more than $105 billion for Ukraine, Israel and U.S. border security, but so far Republicans in the House have said no.
What does Ukraine "winning" mean to you at this point in the war? When you're targeted by a much larger nation state that has every tactical advantage against you, you're going to lose.
Look at every nation the United States has invaded over the last 60 years. Would you say any of them won? When hundreds of thousands of your people die violent deaths, it's hard to declare victory. Even if you remain independent, you lose.
Nope. Germany alone can easily make up for the lack of US support, let alone Germany, France and the UK together. They won't like it and the US will suffer a huge decline in global power-projection capacity, but they'll do it --along with the rest of the EU save Hungary-- because they understand --in a way that many Americans can't-- that Putin cannot be allowed to win.
The other point to make, one that I think is not widely appreciated in the US, is that the Ukrainians will never stop fighting, even if only in the form of a guerrilla insurgency.