@M1991
Yes. If your ex claims the child as a dependent this year, your ex would receive the $3000 child tax credit. Your ex would also receive a $1400 round 3 stimulus payment, since presumably the IRS paid the stimulus that was for your child to you based on previous tax returns.
If you received the stimulus and do not claim your child as a dependent, you do not have to pay the stimulus back. If you received the advanced child tax credit and do not claim your child as a dependent, you would have to re-pay the advanced child tax credit. There is a payment forgiveness scheme for lower income taxpayers, You should review the questions and answers on this IRS web page.
https://www.irs.gov/credits-deductions/2021-child-tax-credit-and-advance-child-tax-credit-payments-t...
While I understand your situation, I can only repeat my general recommendation not to disobey a court order without professional legal advice from your own attorney. Good luck.
