UCE Updates in Already Filed Return (Schedule 1, Line 8)

I filed my taxes in February before UCE $10,200 exclusion went in to effect. I owed both Federal and State (CT) I already made the payments in February.

1. When I download the tax returns from TurboTax today (5/19/2021), it shows UCE - $10,200 on Schedule 1, Line 8. This article says if I see that, then it means my AGI is already recalculated. I do understand that IRS will make the required updates on the Federal return but how is my TurboTax file on record gets updated? I called TurboTax and the lady said IRS makes updates on the TurboTax records. I wasn't convinced that IRS will make updates on TurboTax records. Any idea?
2.  CT State recommends that I file amended return to account for UCE, but TurboTax is not letting me amend only the State returns. It is automatically filing Federal (Just before click 'Submit' it shows it will transfer the record to IRS and I backed off at that point.). How can I amend only CT State returns?

Thank you!