What AGI to use for efile when IRS has not processed prior year tax return

I filed my 2019 income tax return by mailing it in, big mistake by the way.  To date (01-17-2021) IRS has not "processed" my 2019 paper tax return through their "pipeline".  I cannot get a 2019 tax return transcript showing my true 2019 AGI. The IRS magic computer just says it has a statement of non-filing for 2019.  Besides other problems this has already caused me, I anticipate additional problems when I attempt to e-file my 2020 income tax return.

First, assuming that IRS still has not processed my 2019 tax return when I e-file for 2020, what AGI would I use so that an e-file for 2020 would not be rejected for an incorrect prior year AGI?  Would I be better off trying to request an IP PIN from IRS and use that instead of the prior year 2019 AGI?

Second, same assumption as above, would IRS deny a claim for the Recovery Refund Credit on my 2020 tax return since no Economic Impact Payment was received due to IRS looking back to my 2018 tax return to determine eligibility, yet I would be eligible for the EIP based on 2019 AGI which IRS doesn't have in their magic computer yet due to not having processed my 2019 tax return?

Thanks in advance for help on these questions.