Can I get the full $2000 child tax credit if I am amending my return when originally I was not sure if the court order said I got even or odd years?

You could get a maximum of $2,000 for the Child Tax Credit. If you're only getting $1,138 you don't qualify for the full amount. 

• In 2022, the tax credit will be refundable only up to $1,500, depending on your income. 
• Refundable tax credits are treated as payments of tax you made during the year. When the total of these credits is greater than the tax you owe, the IRS sends you a tax refund for the difference.

For additional information, please see Child Tax Credit.

the court order does not control the tax laws. what this means for the CTC is that if you are the custodial parent you get the credit every year unless you furnish the non-custodial parent with form 8332 so they can claim it or probably be in violation of the court order. without that form, they can not claim the dependent and thus the applicable credits.