Yes, you can file your 2021 tax return and I encourage you to do so ASAP.  However, you cannot use TurboTax  e-file to submit your tax return even though IRS "Modernized E-file" system does accept e-filed tax returns using professional tax preparation software for the current and two prior years worth of returns, you must paper file it with TurboTax.

Until you file your tax return, the statue of limitation will stay open forever.  If you do not file your return, IRS will send you notices asking you to file.  If you ignore the notices, IRS will prepare a tax return for you as if you're single with no dependent and no itemized deduction, you won't get any tax refund even if the IRS prepared return shows an overpayment.  In other words, the IRS prepared return will most likely assesses taxes at the highest level.  If you are a chronic non-filer, there could be criminal prosecution.  3 years after the original due date, or 4/15/25, even if you file a tax return and the return shows an overpayment, the overpayment will not be refunded to you.  You will simply lose it.

If you owe taxes, there will be interests and civil penalties tagged on.  Interest is calculated at a statutory rate, compounded daily. Civil penalties are generally assessed at 5% per month, up to 25%.

https://www.irs.gov/individuals/dont-lose-your-refund-by-not-filing

Don’t Lose Your Refund by Not Filing

Many people may lose out on their tax refund simply because they did not file a federal income tax return. By law, they only have a three-year window from the original due date, normally the April deadline, to claim their refunds.

Some people may choose not to file a tax return because they didn't earn enough money to be required to file. Generally, they won't receive a penalty if they are owed a refund. But, they may miss out on receiving a refund.

https://cs.thomsonreuters.com/ua/ut/cs_us_en/utwapp/elf/faq/years-supported-for-e-filing.htm

1040 

• The IRS will accept tax year 2022 electronic files during processing years 2025, 2024, and 2023.
• The IRS will accept tax year 2021 electronic files during processing years 2024 and 2023.
• THe IRS will accept tax year 2020 electronic files during processing year 2023.
• Tax year 2019 (and prior years) returns must be filed on paper.

https://proconnect.intuit.com/support/en-us/help-article/electronic-filing/e-filing-prior-year-retur...

E-filing prior year returns in ProSeries

The IRS Modernized E-File (MeF)system allows returns for three tax years, the current year and the two consecutive prior tax years, to be filed electronically. Most states also follow these rules. Currently this means you can e-file from ProSeries 2022, 2021 and 2020. 

(Note: ProSeries and Lacerte are both Intuit products, used by tax professionals and they both support e-filing 3 years of tax returns.  I don't know why TT doesn't support that.)