Sorry---you are misinterpreting the way the software handles the CTC. If you received the advance payments between July and December, you already received half of the CTC. You only get the other half as part of your 2021 refund. Look on line 28 of your Form 1040. That shows the "second half" that you get now.
PREVIEW 1040
https://ttlc.intuit.com/questions/1901539-how-do-i-preview-my-turbotax-online-return-before-filing
Click on Tax Tools on the left side of the screen. Click on Tools. Click on View Tax Summary. Click on Preview my 1040 on the left side of the screen.
You are correct. There is a Repayment Protection Program for those who might have to repay advanced child tax credit payments. Repayment protection is based on filing status and income levels as you state. Here is a link to the IRS FAQ on the Repayment Protection Program. See question H3-H7.
Lots of users have become very confused by the way the software handles the CTC. People are seeing a great big refund in the "refund monitor" when they begin their return because the software is starting them out with the FULL amount of the CTC as soon as they enter their dependents. Later when they enter the amount they already received for the advance payments, the software reconciles the CTC and takes away the advance payments. To users, it appears they just "lost" some of their refund or that they are repaying the CTC, being taxed, etc etc.etc.
Please ignore the refund monitor until ALL of you information has been entered. The refund monitor does not mean anything you can take seriously until all of your data has been entered.