Not sure what field you’re in but I work for a big online travel agency and I’ve worked in the Hong Kong office (2 years), the Taipei office (2 years), and have visited the Tokyo office a few times.
My impression of work culture in a Western company in Asia in general is that it’s highly dependent on your team. I have most of my team and my direct manager located in London/Dallas, so I have a lot of leeway in when and where I work, but I do have to take a lot of late night and early morning calls. But on those days, I often don’t go into the office at all, or just for a few hours.
It would be different if you were reporting into a local team and a local manager, but would still likely be far better in terms of working hours and environment than any Japanese/Taiwanese/HK company.
In my company, the Tokyo office and other regional offices in Japan are honestly pretty Japanese compared to say Hong Kong, but still not as Japanese as a local Japanese company. I think we have around 150 headcount in Tokyo and probably only 3 or 4 of them are non-Japanese. The hiring profile for our Japanese team is about half locals who have studied English hard enough to get along fine in English language meetings with non-Japanese (that alone is pretty rare in the Japanese workforce), and then about half are “international school” types who are essentially fluent in both Japanese & Western language and culture, and most of them have spent substantial time overseas as kids. I have really enjoyed myself the few weeks I’ve spent in our Tokyo office and I’d consider working there if I got the chance.
Bottom line for any international company is the Tokyo office is likely to be much larger, much more professional, and much more important than the Taipei office, if there even is a Taipei office at all. Exceptions might be chip industry, hardware, and anywhere else Taiwan is strong.
Hope that helps.