Unfortunately, I'm not sure there's much on the pie chart to redirect percentage wise. About 60% goes to non-discretionary programs like Social Security and Medicaid, and 13% is interest expense. While "non-discretionary" programs can potentially be cut, doing so is politically toxic and arguably counter to the goal of a better society.
Of the remaining discretionary portion half is programs like veterans benefits, transportation, education, income security and health (in order of size), and half military.
FY2025 spending in total was 3% over FY2024, with interest expense, social security and medicare having made up most of the increase ($249 billion)[1], and likely will for the foreseeable future[2] in part due to how many baby boomers are entering retirement years.
Assuming you cut military spending in half you'd free up only about 6% of federal spending. Moving the needle more than this requires either cutting programs and benefits, improving efficiency of existing spend (like for healthcare) or raising more revenue via taxes or inflation. All of this is potentially possible, but the path of least resistance is probably inflation.
[1] https://bipartisanpolicy.org/report/deficit-tracker/
[2] https://www.crfb.org/blogs/interest-social-security-and-heal...