To be consistent, I would then also want to get into opting out of end of life healthcare which is where a huge, if not majority, of healthcare spend is.

Social security is not paid by other taxes. It's its own fund.

I do not find that clerical accounts for government expenses matter for practical purposes. Nominally, they can have various funding sources, but a politically popular expense will get its funding from somewhere, somehow.

It seems prudent to just treat all monies paid to the federal government as taxes, and all services/products received from the federal government as a whole when accounting for it as an individual taxpayer.

keeping very sick people alive if way more expensive than keeping older people alive.