I read this one story where MC isekaied to an alternate "real" world, but everyone seems to be chuunibyou, thinking they're xianxia cultivators, when in reality, MC reality warps and interacts with the world differently, so people's elixirs is a loaf of bread to MC, or dharma weapons are smartphones, etc. and MC's loli little sister claims she's a reincarnated immortal empress, swings an umbrella in rainboots