Ok ... the CTC reduces the EV credit by $600 because the non refundable portion must be taken into consideration first ... then the EV credit is used ... so if you have $7600 of tax liability the CTC of $600 will be used first and then the EV credit will max out at $7000 bringing your tax down to zero and the excess EV credit is lost forever.
Now as to your refund ... the rest of the CTC will be refunded as the ACTC (additional CTC) of $1400 plus any other withholding that is not used for non federal tax liabilities like SE taxes.
