Ronda

That's a tough call for me. I think that's about the right amount of time to visit Ronda without running around, but it probably isn't adequate for including a side trip to Grazalema. Transportation in that area is slowish and infrequent. I believe you've already dug into the train and bus schedules in and out of Ronda, so you know there's going to be some extra transportation time required if you add Ronda to your itinerary.

In case you are not aware and would be interested, in the past there have been bus tours to Ronda and one or two of the white villages departing from Seville. It would mean a good bit of time sitting on a bus, I'm sure. I didn't seriously consider that since I wanted to have at least a full day in Ronda. I ended up spending 3 nights in Ronda so I could take a side trip to Grazalema. (Definitely not recommending that to you; I had over a month in Andalucia.) I don't regret seeing Grazalema (finally, on my third trip to Ronda), but I think Arcos de la Frontera (possible by bus from Seville) is more interesting than Grazalema (but less so than Ronda unless you prioritize cute and small).

On balance, I think with your schedule the night in Ronda is worth it. Just be sure you have accurate train/bus schedules for the time of year you'll be traveling. I wonder whether the bus schedule could be rather seasonal.

We recently spent 2 nights in Ronda. Our trip was a bit longer than yours so we could afford those 2 nights. We really enjoyed the town. Went to the guitar show mentioned in RS guide- note- (the location has changed,.
Much to our surprise and delight the King of Spain visited Ronda for the first time ever while we were there. It was 450th anniversary of the bullring so he was there for celebrations. The streets were lined with spectators- including us and it was such a cool experience- he drove right past us- I could have touched him he was that close!
Unfortunately that meant we couldn't visit bullring til next am- but that worked as our bus didn't leave til noon. Very interesting bullring and well done museum.

Did you originally have 6 nights in Sevilla? We did 4 and that was fine for us but no day trips.
What are your plans for 2 nights in Madrid? Since you have been there maybe you could get away with just 1 night in Madrid and give that night to Ronda so you'd have 2?

How long would you stay in Ronda? We plan to arrive mid day and leave
around 5 the following day.

If you can't spare a night from anywhere else then this is actually ok for JUST Ronda- obviously no day trips.

There are periodic discussions here (search box top left, blue) about how tough it is to see the white villages and Ronda by public transportation. We stayed three nights in Ronda with a car. (Seville to Granada) I'm not sure I'd spend 5 nights in Seville, but it's a nice place, with Carmona and Italica close-by visits. I've only been to the Malaga airport, but I question whether it has two nights, except for Picasso scholars.

I will say that people are likely to ask you about Ronda back home, if that matters to you. I take it that Barcelona is for another visit.

Thank you to all who replied.
Yes @acraven I believe the bus schedule does change in the fall but the Alsa app and Damas website help. I’d love to add more time but i have elderly parents/family commitments. We have been fortunate that this is our 4th trip to Spain so we are just sticking to the South.
I’ll look into a day trip to Arcos de la Frontera from Seville and leave Ronda at one night.