See this IRS info
"I was not employed...." Were you claimed as someone else's dependent in 2020 or 2021? If someone else could claim you as a dependent then you were not eligible for the stimulus checks, and would still not be eligible now for the recovery rebate credit -- which is based on your 2020 and/or 2021 situation, not whether you were employed in 2023.
If no one could claim you as a dependent for 2020 or 2021, then you can file tax returns for those years and use the recovery rebate credit in Federal Review to get the stimulus payments. The returns must be filed by mail; they cannot be e-filed.
To file a return for a prior tax year
If you need to prepare a return for 2020, 2021, or 2022 you can purchase and download desktop software to do it, then print, sign, and mail the return(s)
https://turbotax.intuit.com/personal-taxes/past-years-products/
You may also want to explore purchasing the software from various retailers such as Amazon, Costco, Best Buy, Walmart, Sam’s, etc.
Remember to prepare your state return as well—if you live in a state that has a state income tax.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS/state received the return.
Federal and state returns must be in separate envelopes and they are mailed to different addresses. Read the mailing instructions that print with your tax return carefully so you mail them to the right addresses.
Note: The desktop software you need to prepare the prior year return must be installed/downloaded to a full PC or Mac. It cannot be used on a mobile device.
Or use the paper forms and prepare them by hand to mail in:
2020
https://www.irs.gov/pub/irs-pdf/i1040gi.pdf
https://www.irs.gov/instructions/i1040gi
https://www.irs.gov/pub/irs-prior/f1040--2020.pdf
https://www.irs.gov/pub/irs-prior/f1040s1--2020.pdf
https://www.irs.gov/pub/irs-prior/f1040s2--2020.pdf
https://www.irs.gov/pub/irs-prior/f1040s3--2020.pdf
2021
https://www.irs.gov/pub/irs-pdf/i1040gi.pdf
Here is the IRS 2021 Form 1040
https://www.irs.gov/pub/irs-prior/f1040--2021.pdf
or if you want bigger type use 1040SR for Seniors,
https://www.irs.gov/pub/irs-prior/f1040s--2021.pdf
And 2021 Instructions
https://www.irs.gov/pub/irs-prior/i1040gi--2021.pdf
2021 Tax and EIC Tables
https://www.irs.gov/pub/irs-prior/i1040tt--2021.pdf
Sch 1 : https://www.irs.gov/pub/irs-prior/f1040s1--2021.pdf
Sch 2 : https://www.irs.gov/pub/irs-prior/f1040s2--2021.pdf
Sch 3 : https://www.irs.gov/pub/irs-prior/f1040s3--2021.pdf