You're not supposed to get back all of the tax that you paid through withholding or estimated tax payments. You have to pay tax to the government to pay for government services.
From the figures you gave, it looks like the total tax you have to pay for 2024 is $5,507. The $2,000 child tax credit reduces that to $3,507. You paid $4,478 in advance, so you get a refund of $4,478 - $3,507, which is $971. The government keeps the $3,507.
