I want to try a strategy in 2026. Through my W2 job, I will be reducing my Federal Tax withholding to $0 (still paying mandatory FICA) from Q1 until mid Q3 (1/2026-8/2026), and from mid Q3 until Q4 (9/2026-12/2026), put 100% of my pay into Federal withholding.
I will submit a W4 change for the end of January 2026 with a high deduction until $0. Then, I will submit another W4 change for the end of September 2026 to withhold the maximum amount. I found that the IRS treats withholding tax as paid evenly throughout the year (IRC 6654(g)), which satisfies the "pay-as-you-go" requirement (https://www.law.cornell.edu/uscode/text/26/6654). I am fine with eating the potential $500 penalty for not having a valid reason to put high deductions for the first W4.
Am I missing any glaring issues or penalties here?