Quick question about visitors visa!

Hi there so I just graduated college and I plan to visit taiwan for 6 months. Anyway I am basically shadowing a professor in her biology lab, however since I’m not officially a student or an employee I cannot get official documents from the university. I’m wondering if it is possible for me to stay for 6 months with a visitors visa even though I don’t have any documentation. ATM I am a us citizen and I’ve been told I can stay for 90 days without having to get a visa. Thank you!

I tried the visitors visa approach. It was a pain. They made me come in every 60 days to renew,and I had bring all sorts of documentation. They never gave me any hassle so long as I had the paperwork, but it’s the paperwork that’s the hassle.

Hong Kong is nice for a short visit.