If I did not file the 2020 amended return I made with TurboTax, can it be disregarded and its information not used when I do my 2021 taxes?

I clicked on “amend” by mistake

https://ttlc.intuit.com/questions/2552802-how-do-i-cancel-or-undo-an-amended-return-in-turbotax-online

Pay particular attention to steps 4 and 5 in the instructions that xmasbaby0 referred you to. Simply canceling the amended return will not put the information in your 2020 tax return back the way it was. You have to do that yourself.