No, if you don't own a business, you can't deduct the cost of tax prep or tax prep software, at least not on your federal return. The Qualified Business Income (QBI) is based on net income, not deductions, so this isn't related to any deduction.
But you can get a QBI deduction even if you aren't self-employed. In addition to business income, the following are eligible for the QBI deductions:
- Qualified REIT dividends from Form 1099-DIV box 5
- PTP income Schedule K-1 (1065)
- Commodities transactions or foreign currency gains or losses
- Certain dividends and payments in lieu of dividends
- Income, loss, or deductions from notional principal contracts
- Annuities, unless received in connection with the trade or business