I am not a tax professional, so my advice is limited: I believe there is a one-time option for seniors (50+?), to lower the taxes on gains from selling primary home. This may only be for California. I don't think there is an option in the estimated tax section to account for gains specifically on selling your home. The estimated tax section asks fairly simple questions like how much will your total gains be for 2021.
You might try copying your 2020 tax file and go through the 2020 interview with that file. It will probably ask you for details to see if you qualify for the reduction.
I only got involved in this discussion because I knew how to get to the estimated tax section of TurboTax. Maybe someone with more knowledge of you situation will also reply. (I didn't want you think that you were being ignored.)
Good luck!
