I was a non-filer for many years, and I’ve been round the horn with them. They got some, but not nearly all they claimed was owed. All in all it was not such an unfavorable experience for me, and now I file with zero owed each year. No withholding, no refund. No audits.
I pay an accountant quite a bit every year to escape with nowhere near the clearance you do.
I must be doing something wrong.