Book the 08:00 Nasrid Palace slot, not the 10:00
The 10:00 slot is the most popular because it feels civilised. In July it is a mistake. By 10:00 the sun is already high, the Alcazaba terraces are exposed, and the Generalife gardens are starting to bake. The 08:00 entry gets you through the Nasrid Palaces by 09:30, while the carved stucco is still in shadow and the temperature inside the Hall of the Ambassadors is genuinely cool. You can do the Generalife before 10:30 and be back in the city for breakfast before the heat peaks. The 08:00 slot is also the easiest to book — it sounds antisocial and most people skip it.