@taxsoftware is correct.  ProConnect Tax is the same as Lacerte.  It is supported but you'll still need to attach it as a PDF.

This is not a problem unique to Intuit.  My friend uses ATX from CCH and it's the same deal.

Did a bit of Googling.  It would appear this is not even Intuit's fault (like anything ever was?  Tongue in cheek).  Looks like Sch B is just not supported by the IRS' e-file schema yet: https://www.irs.gov/e-file-providers/tax-year-2021-modernized-e-file-schemas-and-business-rules-for-...