The spare ammo and SAMS the Ukrainians need, does not exist.
In the US and the West generally, we produce weapons and ammo in peacetime mode (slowly and expensively), while the Russians have been producing in wartime mode (cheap and fast).
That disparity cannot turn around in less than a decade, if we even make the attempt.
The US has produced @12,000 rounds of Patriot missiles.
And for that matter its got @500 lquncher units in reserve, plus radars and etc in proportion.
There a millions of rounds of 155mm DPICM in the disposition queue. Among lots of other things, like MLRS DPICM.