The IRS just released Schedule D for 2023 today. They still have not released the Schedule D instructions or Form 8949 and its instructions for 2023. Those forms are needed to report capital gains. When the forms aren't available from the IRS, there's not much that TurboTax can do.
You can enter investment sales in forms mode (with the understanding, of course, that the forms aren't final).
You could also try using the What-If Worksheet in forms mode for estimating your 2023 taxes.
