MSPeconomist

OP has Tit status with Starriott/Bonvoy, so I highly recommend staying in Seville in the Alfonso XII (or some other Roman numeral) which is a stunning historic LC property in the center of town.

In Granada there's a nice but expensive Parador that tends to book up very very early. Similarly, Guadalupe has a very nice historic Parador or there's a similar privately run historic boutique hotel. IIRC there are good Paradors in Toledo too (overlooking the city) and Segovia (also a bit outside of the center), where there are roman aqueducts and other ruins. Years ago I was impressed by a Parador about an hour (east along the main road???) from Seville in a Morrish-style palace with a beautiful blue tiled pool down a flower filled hill from the hotel; IIRC it was outside of a village called something like Christiana (???), where I saw some real flamingo dancing at a street festival.

Much of Spain's southern coast is overbuilt with housing for retired Brits and ugly resort complexes, so I would generally avoid, although at this time of year it might be nicer to focus on southern Spain. There's some nice scenery where sherry is made, around Ronda and Jerez de la Frontiera, but you need a car here. Along the coast, I think Valencia is interesting for a historic city and also Alicante (but definitely avoid Benidorm (spelling?) and the surrounding coast.

Now might not be the best time to go to Catalonia with the recent disturbances, especially in Barcelona, although the problems might be over by now and certainly by the time of your trip.

If you're flying into BCN and out from MAD, I'd be tempted to rent a car for most of the way and head south from BCN along the coast initially to Valencia (rather than spending time in Barcelona, although you could take the train for this part) and Alicante and then go inland to Seville, Granada, Toledo, and Segovia (maybe add Guadeloupe along the way, but it's a long tough drive on small winding roads), almost circling back to MAD. If you're interested, check whether it's bull fighting season near Madrid, but I suspect the answer is no.