If you wait you will need to print and mail 2021 return. Yes you can claim the 3rd Stimulus payment as the Recovery Rebate Credit on your 2021 return and the Child Tax Credit.
But you may not be able to finish online or get a printout to mail in after online closes.
How to mail a return from the Online version
How do I print and mail my return in TurboTax Online?
Be sure to attach copies of your W2s and any 1099s that have withholding on them. You have to mail federal and state in separate envelopes because they go to different places. Get a tracking number from the post office when you mail them for proof of filing.
