An aspect of spending on financial enforcement that most people don't understand but is well-understood by government auditors is that too much enforcement has a negative ROI to the government separate from the cost it imposes on the economy.
Most financial recoveries via enforcement is not waste or corruption in the traditional sense, it is from insufficient financial compliance processes. The requirements for these processes are fuzzy, so you can always squeeze a little blood from this stone if auditors try hard enough. People react to this pressure by engaging in ever more compliance activity, without much concern about its effectiveness for its nominal purpose. So far so good.
The government realized many decades ago, as an organization that buys trillions of dollars in goods and services from the private sector, that these compliance costs it was creating were effectively being billed back to the government, in many cases in excess of any value created by the compliance processes. In most cases, we are already way past the point where spending more money on enforcement is productive but it is politically popular so it happens anyway. The optimal amount of fraud and waste is not zero, and to the extent things look like waste it is usually because compliance processes have required it to look that way to avoid enforcement actions.
A much better approach would be to revisit the effectiveness and utility of the compliance processes the government creates through enforcement actions, which currently has few if any limiting principles in practice. These are not free, either to the economy or to the government which has to pay for those compliance costs when it buys things.