"isn't there an associated entry under Deductions and Credits (Trad and Roth IRA contributions)?"
Generally, no. If after-tax basis was rolled over to the traditional IRA, is to be entered into TurboTax only for the year when there some other change to traditional IRA basis required to be reported on a Form 8606 Part I. If there were no regular nondeductible traditional IRA contributions and no traditional IRA distributions made in 2023, no 2023 Form 8606 Part I is needed.
"Also, if the 1099-R is for a 'combined' rollover (2 in-plan rollovers of after-tax cost basis to Roth IRA and earnings to Trad IRA) should they be input as 2 separate 1099-R events?"
Distribution split as rollovers with a portion going to a traditional IRA and the rest going to a Roth IRA require splitting the Form 1099-R into two to accommodate TurboTax's limitations, one from the portion rolled over to the traditional IRA and another for the portion rolled over to the Roth IRA.
