The Yangtze River Delta has been a wealthy region since ancient times, and the Pearl River Delta is also a productive region. Because the two regions are economically developed, transportation facilities, urban construction, food culture, medical conditions, etc. are not very different, so the comparison of the retirement settlement is more from the climate and environment to compare.
The Pearl River Delta (PRD) region has a subtropical oceanic climate, and is one of the regions with the smallest average annual temperature difference in China. The PRD has relatively short winters, autumns, and springs, and up to nine months are summer, which is basically summer in the PRD, and I think it's still a good idea to settle down and retire in the PRD.