@Iwantthetruth92 All my T3 Statements with values in Box 21 have values provided for Box 52 & 53, which should total the same as Box 21.
My specific advice is to enter all values for Boxes 21, 52, & 53 in the TurboTax T3 entry form as "Capital Gains". Do not enter any values in the Boxes 21, 52, & 53 labelled as "Foreign Capital Gains". This should eliminate the errors you cite and allow you to NetFile.
The original purpose of Box 52 & 53 was to report Capital Gains before and after 24 June to apply the new tax rate. Although this no longer applies, CRA has apparently insisted that the values still be reported. If you have received a T3 Statement that doesn't show values for box 52 & 53 and TurboTax is giving you an error, just enter the total Capital Gains in Box 53 to balance the equation. Box 52 & 53 no longer have any tax implications for 2024. A huge mess that is affecting thousands of tax payers and which TurboTax is not coping with.
