Higher frequency means less range (everything else being equal) but not more interference. Interference depends on how used / crowded a given piece of frequency

Higher frequency means less range (everything else being equal) but not more interference. Interference depends on how used / crowded a given piece of frequency is, and the 5 GHz band is much less crowded than 2.4 GHz: there is more spectrum there, less 5 GHz devices, and because the range is smaller the interference from neighbors is lower.