I can appreciate that you are confused by conflicting advice. The IRS never states that you must have 2021 earned income, only that if your 2019 earned income is higher, you can use that. Obviously any earned income in 2019 is higher than zero in 2021. In the EIC qualification assistant use your 2019 amount when asked for your earned income. That’s what the law allows.
In TurboTax go to deductions and credits and click on eic and you will be asked “If your 2019 earned income is higher than your 2021 earned income of $0.0, you could get more for the EITC”
