The statement that Form 8453-S is "not available for e-filing" is misleading.
In TurboTax Business, the form is printed, signed, scanned, and then uploaded as a file so the 1120-S return package can be e-filed.
The delay is typically short between approval and the e-file acceptance date. For example, TurboTax will start accepting e-filed returns on 1/24/2022 and Form 8453-S will be available on 1/28/2022.
