Andalucia / Madrid itinerary - are we trying to do too much?

I'd say so. Any particular reason you're going to so many different places in 11 days? I would just pick 3 cities max.

Since you will have a rental car, rather than visiting Córdoba as a day trip, go from Ronda to Córdoba and spend a night, then go to Sevilla to turn in the vehicle. Córdoba is only a couple hours drive from both Ronda and Sevilla. By spending a night in Córdoba you could see more of the city.

You could also switch the itinerary and go from Granada, to Córdoba, to Ronda, then Sevilla. To give you more time in Sevilla you could cut one night from Madrid.

I feel that while fast paced, it is doable, although there is a lot of travel time getting from place to place. Since you’re coming from London, unless it’s just a layover, there shouldn’t be any jet lag giving you more time on arrival day to see Malaga.

We are spending 4 nights in London visiting my son. We have never been to Madrid, and thought it made sense to add Madrid as we have better options to fly home. We added Malaga for a night since we are going to fly from London to Malaga. Do we keep Malaga for a night? Worth spending a night in Ronda? Have even considered not spending anytime in Madrid - but don't know if/when we may get back there.

We stayed in all those sites except Malaga during our first visit to Spain in 2023, a stay of 11 nights. We added a one night stay in Cordoba based on advice from Forum members, and were glad we did. We found Ronda worth at least one night (though we were happy to have stayed two). We drove the Granada-Ronda-Sevilla route, though in the opposite direction from your draft itinerary. For your reference, here is our trip report which includes details on our drives and our activities in each location: https://community.ricksteves.com/travel-forum/trip-reports/trip-report-spain-aug-sep-seville-ronda-granada-cordoba-madrid

For me, the main issue with your itinerary is the single full day (plus some hours) you'll have in Seville. There's a lot to see in Seville; I'd want to have three full days there. Unless you're big art fans for whom Madrid's art museums are a major draw, I'd recommend shifting one night from Madrid to Seville. It's not that Madrid isn't worthwhile, but to me Seville is a more distinctive city. And it will be easier to return to Madrid on a future trip if you want to do that.

For the trip from Malaga to Granada, you might take a look at the bus schedule as well as the train schedule. There aren't very many trains in and out of Granada, so some visitors end up taking a bus instead. Spain's intercity buses are quite comfortable. Although the train may be faster, in many cases the bus takes a more direct route, so there may not be much difference in the trip duration, and I think buses are more frequent.