First, Ukraine isn't collapsing, that's the Russian narrative in an attempt to A) cut support, B) make westerners put pressure on Ukraine to give away their territory. Nonetheless, cut funding from the biggest financial backer would of course be a massive blow.
Second, last I checked, members of the Rep party are blocking the Ukraine funding.
Third, Ukraine uses American support to buy American supplies. Meaning it is essentially a job subsidy for Americans, with fewer unemployed in the US than would otherwise be the case.
Ukraine is a war that the US (and Europe) will easily help Ukraine win, if we want to, as we have a massively larger economy than Russia. This is far worse situation than the Afghanistan for Russia with the toll closing in on half a million dead and wounded Russians fast. Defeatists and Kremlin puppets however are of course trying to do their best to sink western support. And it's honestly depressing to see the number of idiots running their errands.
Show some pride of your country, the US is still the mightiest nation in the world, and unlike the shit wars it got involved in since the 90s this one is actually worth fighting for, because we have all the moral right here to save Ukraine from genocide. (I say we because as a European we are allies after all.) And winning this prevents further wars, when nobody lifts a finger it encourages dictatorships everywhere to invade their neighbors.