For 2020, the child tax credit is a maximum of $2000. If you don't owe any tax because of low income, you can get up to $1400 per child, but this depends on how much income you have from working--it's not free money, the more you work, the more credit you get. What Turbotax told you is what you get.
For 2021, the credit will be $3000 (or $3600 for children under 6) and you don't have to work to get it. This is a temporary change so far, and the credit will go back to the old rules for 2022, unless Congress passes another update to the law.
