Which is better, HarmonyOS Tianji or Snapdragon?

There is no comparison. HarmonyOS system is Huawei's operating system, and Tianji and Snapdragon are processor models, which can't be compared. HarmonyOS system refers to Huawei's HarmonyOS system and Huawei's HarmonyOS system OS, which was officially released by Huawei at the Huawei Developers Conference (HDC.20 19) held in Dongguan on August 9, 2065438.