Roth overfunded in 2024; deadline for converting to traditional IRA if filing extension? I understand I will later receive a 1099R, do I input in 2025 even tho the conversion will be reflected in Turbo Tax 2024?

The deadline for recharacterizing (not converting) to a traditional IRA is October 15, 2025 if you request a filing extension or file your 2024 tax return by April 15, 2025.

Again, it's not a conversion.  The movement of the funds from the Roth IRA to a traditional IRA is a recharacterization which causes the contribution to be treated as if it had originally been made to the traditional IRA.  To report the recharacterization in TurboTax you must enter the original Roth contribution, then tell TurboTax how much of this contribution (without regard to any earnings) was "switched" to be a traditional IRA contribution instead.  TurboTax will then prompt you to prepare the required explanation statement.

If you subsequently decide to to a Roth conversion from the traditional IRA to a Roth IRA, that will be reportable on the tax return for the year in which you do the Roth conversion.