People are homeless not because the government lacks funding, but because the government doesn’t give a damn. Those billions being given to Ukraine were never going to be spent addressing poverty had the war not happened, and if Congress suddenly had a change of heart, they’d have zero problems finding and allocating as much money as they want to anti homeless programs Ukraine war or not
Western doctrine is also largely based on the US’ needs. Artillery just isn’t practical for the US, who needs to be prepared to fight all over the world oceans away from home. Artillery is much more stationary compared to air power due to the size of the guns and the difficulty moving them, while the US can easily fly planes anywhere we need them. As such, Western doctrine became heavily reliant on having air supremacy and massive amounts of air support and our equipment was designed for that battlefield. Ukraine just doesn’t have nearly the same arial capabilities as NATO, relying much more on artillery which NATO weapons and doctrine weren’t designed around, and they’re having to figure out how to make them work without air power