When I make estimated tax pymts on the IRS site to avoid a large payment due April 15th (plus interest), should I be entering those "pre-payments" on line 26 of my 1040?

Yes, if you made estimated or quarterly tax payments in 2022 toward your federal tax,  the amount paid goes on form 1040 line 26.

To report estimated payments paid in TurboTax :

1. Open or continue your return
2. Go to the Federal section, then Deductions & Credits
   • You can also search for estimated tax payments and select the Jump to in the search results
3. Select Estimates and Other Taxes Paid
4. Select Start or Revisit next to Estimated Tax Payments
5. Choose Start next to the type of estimated tax payment you'd like to enter
6. Enter the amount of estimated tax you paid at each of the quarterly due dates