Where do I find Section 179 Expense Deduction that was disallowed in 2021?

If the SEC179 is on the landscape 4562's from 2021 and 2022, there's nothing to recover. The deduction was taken in 2021, and that's it.

Otherwise, if it's not on the 2022 landscape 4562, then all I know to do is clear the return and start over from scratch. How you do that, depends on if you're using the CD version or the online version. I don't know how to deal with the online version. (I find it very limiting and user-unfriendly). With the CD version you just delete the .tax2022 file in the documents\turbotax directory. Then when you start the TTX program again it's "as if" you're starting it from the very first time.

Then you can do a fresh import from the 2021 return.