Under the rules for 2022 and 2023, you're only entitled to receive Child Tax Credit up to the amount of your tax liability. The amount of Child Tax Credit you can receive has changed since pandemic-period legislation allowed for a much larger amount in tax year 2021.
The actual amount of Child Tax Credit you'll actually receive for 2023 is probably significantly lower than $4,200. If your AGI is roughly $31,000, your taxable income -- generally, your AGI minus your Head of Household standard deduction of $20,800 -- would be roughly $10,000. The tax for Head of Household on $10,000 would be $1,003 -- see the IRS' Tax Tables.
Under the rules for tax year 2023, you're only entitled to receive Child Tax Credit up to the amount of your tax liability. So, if your tax liability is roughly $1,000 or thereabouts, that's the amount of Child Tax Credit you'll receive.
See the TurboTax Help article Why is my 2023 Child Tax Credit smaller than last year's? for more information.
