There has been a long standing contentious battle over whether or not the IRS's Income Tax Returns are voluntary or not. This is discussed here at https://www.irs.gov/businesses/small-businesses-self-employed/anti-tax-law-evasion-schemes-law-and-arguments-section-i
It is also of note that a former IRS Commissioner Steve Miller admitted the voluntary nature on C-Span here https://www.c-span.org/clip/house-committee/user-clip-former-irs-head-steve-miller-admits-income-taxes-are-voluntary/4455340#:~:text=User%20Clip%3A%20Former%20IRS%20Head%20Steve%20Miller%20Admits%20Income%20Taxes%20are%20Voluntary,-IRS%20admitts%20Tax
I once took such a position and was quickly hammered into compliance. It is quite a rabbit hole. Here is a good depiction of my experience:
