Waste is not just related to spending, but how the spending is done.
Spending that goes to low income categories has a massive multiplier effect as each $ is immediately spent on essentials, and typically goes to small businesses, grocery stores etc... which in turn spend - so with each spend cycle involved there is a multiplication of the benefit for the initial spend (and an associated tax return, decreasing the net spend).
Spending which goes to high income categories (wealthy individuals, large corporates) quickly gets offshored into tax havens, it has benefit, but it is basically a single cycle, as opposed to the multi cycle nature of spending on low income categories.
The way to build up a nations GDP and boost its tax income as well as reducing debt etc.... is to spend more at the low end, medical benefits, social security, pensions, education etc... There is a strong and demonstrable "trickle up effect" (but contrary to decades of conservative propaganda, no demonstrable "trickle down").
Close the corporate loopholes, tax high income categories (both corporate and individual), combined with low income spending, and much of the budget deficit would start to disappear.