You’re going to be living in Kaohsiung soon. Chaishan Park just on the edge of the city is loaded with them. They get pretty aggressive.
I saw a monkey about 3 hours ago. We were out at Wawagu near Wulai (just south of Taipei), looking at a gorgeous waterfall when one climbed up out the branches above us.
Alishan. Take the morning sunrise bus to Tatajia (Yushan) and the bus stops at a monkey crossing area.
I believe people say you can see them in Tienmu (northern Taipei) on the trail up to the cultural university.
If you really want to see them join the hiking club when you come back. Omniloquacious will set up a river tracing hike where you may just get to swim in a tropical river pool while monkeys play above you in the branches.
If you’re not finding monkeys in taiwan, you just aren’t trying hard enough.