Just as sad ... you will probably get a notice from the IRS telling you that they have a payment for 2019 but no return was filed that you will need to respond to by mailing in a signed return. Also send a copy of the acceptance email and/or the efiling history page in the PDF.
So did you check your account transcript ? https://www.irs.gov/individuals/get-transcript
Was the return ever actually processed ?
If you efiled electronically then you can use the IRS Where's My Refund? tool to check on the return ... the trick to using the refund tool when you had a balance due is to enter $1 for the refund expected and they now have 2019, 2020 & 2021 available on that tool : https://www.irs.gov/refunds
