we can't see your return which creates issues in determining all the credits your eligible for. generally, the credits you are likely to get are the dependent credit of $500 on line 19 of 1040 and the earned income credit on line 27 of 1040. however, the earned income credit and dependent credit are phased out if you net self-employment income is too high. There will be "NO" on that line. Being the custodial parent, the IRS says you don't need your exes or courts permission to claim the child. However, if the court order you to grant the exemption to your ex, then you could be taken to court for claiming the dependent. you also get a higher standard deduction filing as head of household.
for the other dependent credit look for form 8812. the earned income credit would be on form EIC.
note that the rules for the child tax credit were substantially changed for the year 2022 so you may have gotten it in 2021 but not in 2022.
