Claiming Recovery Rebate credit (for EIP3) while payment trace is in progress - filing 2021 taxes

My mom got Form 6475 early this year but never received the actual check. She didn't realize it until now because she's filing her 2021 taxes (federal and state) ahead of October 17th deadline. I have asked her to contact IRS and start a payment trace but it takes six weeks to get an answer.

Question is: If the trace is NOT complete by October 17th and she has to absolutely file by then, should she say she received $0 in EIP3 and thus get TurboTax to claim the EIP3 amount as Recovery Rebate credit? What is the consequence, and / or are there better options to handle this?

Thanks,

JS