There is a reddit page on paper tax return: https://www.reddit.com/r/IRS/comments/m9dqc0/paper_tax_return/?utm_source=share&utm_medium=web2x&con...
The delay is widespread, I heard a case that someone sent in 2019 tax return in April, 2020 and IRS didn't show they received it until February 2021. It takes them 10 months to open the envelope. That is how slow it is!
