In your case, your 2020 Adjusted Gross Income (AGI) is too high, so you don’t qualify for EIC, whether you use your 2019 or 2020 earned income. That’s why the program isn’t giving you the option.
The Earned Income Credit for 2020 is computed by comparing two amounts in the IRS's EIC table -- an amount based on earned income – which can be from either 2019 or 2020 -- and an amount based on your 2020 AGI. Whichever of these two amounts from in the table yields the smaller EIC amount will be used.
Here, your AGI is too high, so it doesn’t matter which year you use for earned income.
Please see Worksheet A -- 2020 EIC -- Line 27 in 2020 Instructions for Forms 1040 and 1040-SR to see how the computation works.
