No. A 2020 Schedule K-1 has to be entered on a 2020 tax return.
You will have to amend the 2020 tax return that was filed to add the Schedule K-1
See this TurboTax support FAQ for amending a 2020 tax return originally completed and filed using TurboTax - https://ttlc.intuit.com/community/amending/help/how-do-i-amend-my-return/00/27439
