Offhand, I'm unaware of where to even look to get an easy to digest version of 'where tax dollars go'. Would the GAO make such a report? Something for Congress otherwise? Would there be a classified and an public version?

Even better would be a tool that, E.G. with your IRS filing number, shows how much 'you' paid in, breaks down where that went, and shows how 'you' compare to other areas.

Such tools and reports would cost money, but making them is practically an audit anyway which is a good use of resources in a bureaucracy (part of the self-calibration system).