@LAP5771:
"I am over 59 1/2, but have been doing some Roth Conversions lately, so I have to be careful about the five year rule since doing a conversion opens up the potential for being taxed AGAIN as ordinary income."
Incorrect. Because your first contribution to a Roth IRA was for some year prior to 2019 and you are over age 59½, any distribution you receive from any of your Roth IRA accounts is a qualified distribution, free of tax and penalty. The 5-year rule for conversions no longer applies after age 59½.
"I am afraid Turbotax will not allow me to input the contribution basis for this and all other contributions"
Why are you afraid? TurboTax allows this, but it's probably not even necessary because your distribution would be a qualified distribution.
"Turbotax will then fill out the Form 8606"
No, TurboTax will not prepare Form 8606 Part III. Because your distribution would be a qualified distribution, it's not reportable on Form 8606. By telling 2023 TurboTax that your first Roth IRA contribution was made for some year prior to 2019, TurboTax will treat the distribution as a qualified distribution even if the Form 1099-R has code T instead of code Q.
