We would like to take another RS tour to southern Spain. Do any of the available tours in the south NOT overlap with the previous "Best of" tour that we've taken in the past?
There is only one Southern Spain tour, so you will just have to look at the itinerary to see if it meets your requirements.
https://www.ricksteves.com/tours/spain/andalucia#tour-dates
All the Spain tours are listed here:
https://www.ricksteves.com/tours/spain
The Best of Andalusia looks like it would be good for you. It does overlap at the end but Best of Spain doesn’t stay in Ronda, so that’s different and who wouldn’t want to go back to Sevilla and Granada. (A second meal like that one you had on BOS overlooking the Alhambra) wow.
Best of Spain does spend a night in or near Ronda. Looks to me like quite a bit of overlap between the two tours. While the BOS tour doesn't include Cordoba, it's easy to add Cordoba at the end on your own, as I did. Still, if you liked the first tour and want to go back to Andalucia, I'm sure the Andalucia tour will be a deeper dive. Compare them on the website.