As your first year in the US on a F1 visa, you and your spouse are Nonresident Aliens. That means you would file Form 1040NR (which does not allow a Joint return), but TurboTax is not able to file that form. You may consider going to a tax professional that SPECIALIZES in Nonresident Aliens.
The stimulus ("recovery rebate") is not available to you because you and your spouse are a Nonresident Aliens, even if your children are US Citizens.
If you were in the US for over half of 2021, yes, you should qualify for the refundable Child Tax Credit.