You folks all missed my point.  I was complaining about TT not supporting e-filing of the two previous tax years returns.  I specifically pointed out he needed to paper file his 2021 tax return even though all the PROFESSIONAL tax software support e-filing of 3 years returns with Modernized E-file.  My question is why doesn't TT do the same?

At no time did I suggest the OP buy any professional tax software so he could e-file his 2021 return,  The cost would be prohibitively high.  I know because I had used Lacerte for decades before I retired.  Support from Intuit has declined since Lacerte was bought out by Intuit, most likely to keep the bottom line up.  It seems to me TT is no different as demand for e-filing delinquent return is probably not high.

This is my first year using TT.  I find it tedious.  TT doesn't remember all the previous answers and asks many same questions over and over again.  IRS also now permits e-filing of amended and superseding tax returns.  Have no idea if TT supports that.  If not, it should.

IRS recently submitted a Direct File report to Congress, see IR-2023-103.  Hopefully, with competition, TT will provide better services.

Direct File page from a former employer of mine:

https://kpmg.com/us/en/home/insights/2023/05/tnf-irs-report-e-filing-sy[product key removed]am.html

IRS report on potential free e-filing system; pilot program for 2024 filing season

Feasibility of providing a free, voluntary, IRS-run electronic filing system