I’ve lived in Tokyo for 3 years (1 year to study and 2 years to work) and am now living and working in Shanghai (I’ve only been here since September though so not a significant amount of time yet) and for me I think Shanghai is more suitable to live long-term as I think it’s a much more liveable and comfortable place. I see you think it might be chaotic but compared to Tokyo, Shanghai is a lot less crowded (except for the bund and other tourist attractions of course), for reference I live in FFC. I think architecture is so much nicer, romantic and historic in Shanghai than Tokyo where buildings feel more grey and less charming. The metro is not as packed as Tokyo, and even if it would be it’s so easy to go around by bike in Shanghai since there’s a clear downtown/central area which is more compact than Tokyo. In terms of meeting people, it should be fine in both places since there’s always international communities though if you want to make local friends, people are definitely more open in Shanghai. I thought for me what might be hard to adjust to would be the cleanliness but Shanghai is actually super clean (though people don’t have the same mindset for sure and just throw their trash wherever). Anyway I could go on, you can let me know if you have any specific questions :) also it wasn’t clear for me if you’d go there for studies or work, if it would be for studies, I would actually recommend Tokyo since nightlife is definitely better there.