We don't send literal dollars to Ukraine. We send some cash, but mostly we send billions of dollars worth of equipment, ammo, meds, etc.. Those who benefit are those under contract to make the goods and those who sell their consulting services.
IE: the defense sector who supports who ever feeds them. Pub, Dem, they don't give a flying F so long as the money flows.
It's really just the same big money laundering scheme that has gone on for decades. The problem with this one is that it is leaving the US extremely vulnerable to shortages should we get into a war ourselves.