The qualified business income deduction came about in the 2017 Tax Cuts and Jobs Act.
If your situation is basically unchanged in 2018, 2019, and 2020 you should review those 3 years' returns to determine if there was an oversight that can be remedied by amending your return for the QBI deduction.
While you are at it, check for any overlooked expenses as well.
What is the Qualified Business Income (QBI) deduction?
Expenses You May Have as a Self-Employed Person
