FWIW, I move my family between iPhones every year and haven’t noticed any data loss. One exception to date is WeChat, for some godforsaken reason they only back up the most recent dozen conversations or so, so if you want your entire history, you have to jump through hoops to initialize a device-to-device transfer over WiFi, which can take an entire night in worst case.
Would be curious to hear what kind of data loss you have seen though?
Oh yeah, I am under no illusion about WeChat’s privacy. It’s insanely integrated into everyday life in China though - it almost feels as if people don’t care whether they use iOS or Android there, because they use WeChat apps for everything (banking, utilities, taxi, games, payments for everything, etc) rather than native apps.
I'm curious how you came to this conclusion. WeChat is owned by Tencent which is heavily regulated by the Chinese Government since every company needs a Internet license to operate. It's a lot easier for the Chinese government to force Tencent to hand over the information willingly compared to the US getting the information in other ways.
Would be curious to hear what kind of data loss you have seen though?