Simple answer: the entire amount, in box 7, of a 1099-Misc is taxable income. Technically, it is "reportable" income. Your "taxable income" is after all deductions have been taken.
As others have said, Schedule C income is subject to Self Employment Tax (SET), as well as income tax. SET is how the self employed pay their social security (12.4%) and medicare tax (2.9%). There is a $137,700 (2020) cap on the amount of income subject to social security tax. So, if your W-2 income is close to this, not all your self employment income will be subject to the social security portion of SET
