Day 1: Alcázar at opening, then Cathedral and Giralda in the same stretch, Santa Cruz without entry pressure — evening in the centre; flamenco only if you actually reserve.
Day 2: cross the bridge early, market and ceramics in the morning, lunch in Triana, riverbank afternoon — return toward Arenal/lower centre for dinner; Betis for views, not default dinner quality.
Day 3: Plaza de España early, Parque de María Luisa right after, back to the centre for lunch — afternoon for Setas or catching up on day-1 essentials you skipped.