Home office Expenses not included in 2020's return (should've been) but putting in 2021. How to enter home office depreciations, etc?

[mon411]

Home Office use started in Nov. 2019 but was not entered in Fed or CA tax returns for 2019 or 2020.

2021 TT asks for how (actual or simplified deduction) home office expenses were entered in 2020, but they weren't entered, and so what to select there?

Also, prior year depreciations for home office and whole house/home office assets are zero (not in returns) but have start dates in 2019 and 2020. So, TT is calculating year 2 or 3 for the assets.  Should I manually change the "year of depreciation" in the forms to "1" for the assets?  Or should I change the assets' acquired/placed in service dates to be 1/1/2021?

Maybe I should amend my 2020 Fed and CA tax returns?

Thank you!

[Anonymous_]

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